#include "stb_image.h"


#if defined(STBI_ONLY_JPEG) || defined(STBI_ONLY_PNG) || defined(STBI_ONLY_BMP) || defined(STBI_ONLY_TGA) || defined(STBI_ONLY_GIF) || defined(STBI_ONLY_PSD) || defined(STBI_ONLY_HDR) || defined(STBI_ONLY_PIC) || defined(STBI_ONLY_PNM) || defined(STBI_ONLY_ZLIB)
#ifndef STBI_ONLY_JPEG
#define STBI_NO_JPEG
#endif
#ifndef STBI_ONLY_PNG
#define STBI_NO_PNG
#endif
#ifndef STBI_ONLY_BMP
#define STBI_NO_BMP
#endif
#ifndef STBI_ONLY_PSD
#define STBI_NO_PSD
#endif
#ifndef STBI_ONLY_TGA
#define STBI_NO_TGA
#endif
#ifndef STBI_ONLY_GIF
#define STBI_NO_GIF
#endif
#ifndef STBI_ONLY_HDR
#define STBI_NO_HDR
#endif
#ifndef STBI_ONLY_PIC
#define STBI_NO_PIC
#endif
#ifndef STBI_ONLY_PNM
#define STBI_NO_PNM
#endif
#endif

#if defined(STBI_NO_PNG) && !defined(STBI_SUPPORT_ZLIB) && !defined(STBI_NO_ZLIB)
#define STBI_NO_ZLIB
#endif

#include <stdarg.h>
#include <stddef.h> // ptrdiff_t on osx
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
#include <math.h> // ldexp, pow
#endif

#ifndef STBI_NO_STDIO
#include <stdio.h>
#endif

#ifndef STBI_ASSERT
#include <assert.h>
#define STBI_ASSERT(x) assert(x)
#endif

#ifdef __cplusplus
#define STBI_EXTERN extern "C"
#else
#define STBI_EXTERN extern
#endif

#ifndef _MSC_VER
#ifdef __cplusplus
#define stbi_inline inline
#else
#define stbi_inline
#endif
#else
#define stbi_inline __forceinline
#endif

#ifndef STBI_NO_THREAD_LOCALS
#if defined(__cplusplus) && __cplusplus >= 201103L
#define STBI_THREAD_LOCAL thread_local
#elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
#define STBI_THREAD_LOCAL _Thread_local
#elif defined(__GNUC__)
#define STBI_THREAD_LOCAL __thread
#elif defined(_MSC_VER)
#define STBI_THREAD_LOCAL __declspec(thread)
#endif
#endif

#ifdef _MSC_VER
typedef unsigned short stbi__uint16;
typedef signed short stbi__int16;
typedef unsigned int stbi__uint32;
typedef signed int stbi__int32;
#else
#include <stdint.h>
typedef uint16_t stbi__uint16;
typedef int16_t stbi__int16;
typedef uint32_t stbi__uint32;
typedef int32_t stbi__int32;
#endif

// should produce compiler error if size is wrong
typedef unsigned char validate_uint32[sizeof(stbi__uint32) == 4 ? 1 : -1];

#ifdef _MSC_VER
#define STBI_NOTUSED(v) (void)(v)
#else
#define STBI_NOTUSED(v) (void)sizeof(v)
#endif

#ifdef _MSC_VER
#define STBI_HAS_LROTL
#endif

#ifdef STBI_HAS_LROTL
#define stbi_lrot(x, y) _lrotl(x, y)
#else
#define stbi_lrot(x, y) (((x) << (y)) | ((x) >> (32 - (y))))
#endif

#if defined(STBI_MALLOC) && defined(STBI_FREE) && (defined(STBI_REALLOC) || defined(STBI_REALLOC_SIZED))
// ok
#elif !defined(STBI_MALLOC) && !defined(STBI_FREE) && !defined(STBI_REALLOC) && !defined(STBI_REALLOC_SIZED)
// ok
#else
#error "Must define all or none of STBI_MALLOC, STBI_FREE, and STBI_REALLOC (or STBI_REALLOC_SIZED)."
#endif

#ifndef STBI_MALLOC
#define STBI_MALLOC(sz) malloc(sz)
#define STBI_REALLOC(p, newsz) realloc(p, newsz)
#define STBI_FREE(p) free(p)
#endif

#ifndef STBI_REALLOC_SIZED
#define STBI_REALLOC_SIZED(p, oldsz, newsz) STBI_REALLOC(p, newsz)
#endif

// x86/x64 detection
#if defined(__x86_64__) || defined(_M_X64)
#define STBI__X64_TARGET
#elif defined(__i386) || defined(_M_IX86)
#define STBI__X86_TARGET
#endif

#if defined(__GNUC__) && defined(STBI__X86_TARGET) && !defined(__SSE2__) && !defined(STBI_NO_SIMD)
// gcc doesn't support sse2 intrinsics unless you compile with -msse2,
// which in turn means it gets to use SSE2 everywhere. This is unfortunate,
// but previous attempts to provide the SSE2 functions with runtime
// detection caused numerous issues. The way architecture extensions are
// exposed in GCC/Clang is, sadly, not really suited for one-file libs.
// New behavior: if compiled with -msse2, we use SSE2 without any
// detection; if not, we don't use it at all.
#define STBI_NO_SIMD
#endif

#if defined(__MINGW32__) && defined(STBI__X86_TARGET) && !defined(STBI_MINGW_ENABLE_SSE2) && !defined(STBI_NO_SIMD)
// Note that __MINGW32__ doesn't actually mean 32-bit, so we have to avoid STBI__X64_TARGET
//
// 32-bit MinGW wants ESP to be 16-byte aligned, but this is not in the
// Windows ABI and VC++ as well as Windows DLLs don't maintain that invariant.
// As a result, enabling SSE2 on 32-bit MinGW is dangerous when not
// simultaneously enabling "-mstackrealign".
//
// See https://github.com/nothings/stb/issues/81 for more information.
//
// So default to no SSE2 on 32-bit MinGW. If you've read this far and added
// -mstackrealign to your build settings, feel free to #define STBI_MINGW_ENABLE_SSE2.
#define STBI_NO_SIMD
#endif

#if !defined(STBI_NO_SIMD) && (defined(STBI__X86_TARGET) || defined(STBI__X64_TARGET))
#define STBI_SSE2
#include <emmintrin.h>

#ifdef _MSC_VER

#if _MSC_VER >= 1400 // not VC6
#include <intrin.h>  // __cpuid
static int stbi__cpuid3(void)
{
   int info[4];
   __cpuid(info, 1);
   return info[3];
}
#else
static int stbi__cpuid3(void)
{
   int res;
   __asm {
      mov  eax,1
      cpuid
      mov  res,edx
   }
   return res;
}
#endif

#define STBI_SIMD_ALIGN(type, name) __declspec(align(16)) type name

#if !defined(STBI_NO_JPEG) && defined(STBI_SSE2)
static int stbi__sse2_available(void)
{
   int info3 = stbi__cpuid3();
   return ((info3 >> 26) & 1) != 0;
}
#endif

#else // assume GCC-style if not VC++
#define STBI_SIMD_ALIGN(type, name) type name __attribute__((aligned(16)))

#if !defined(STBI_NO_JPEG) && defined(STBI_SSE2)
static int stbi__sse2_available(void)
{
   // If we're even attempting to compile this on GCC/Clang, that means
   // -msse2 is on, which means the compiler is allowed to use SSE2
   // instructions at will, and so are we.
   return 1;
}
#endif

#endif
#endif

// ARM NEON
#if defined(STBI_NO_SIMD) && defined(STBI_NEON)
#undef STBI_NEON
#endif

#ifdef STBI_NEON
#include <arm_neon.h>
// assume GCC or Clang on ARM targets
#define STBI_SIMD_ALIGN(type, name) type name __attribute__((aligned(16)))
#endif

#ifndef STBI_SIMD_ALIGN
#define STBI_SIMD_ALIGN(type, name) type name
#endif

///////////////////////////////////////////////
//
//  stbi__context struct and start_xxx functions

// stbi__context structure is our basic context used by all images, so it
// contains all the IO context, plus some basic image information
typedef struct
{
   stbi__uint32 img_x, img_y;
   int img_n, img_out_n;

   stbi_io_callbacks io;
   void *io_user_data;

   int read_from_callbacks;
   int buflen;
   stbi_uc buffer_start[128];

   stbi_uc *img_buffer, *img_buffer_end;
   stbi_uc *img_buffer_original, *img_buffer_original_end;
} stbi__context;

static void stbi__refill_buffer(stbi__context *s);

// initialize a memory-decode context
static void stbi__start_mem(stbi__context *s, stbi_uc const *buffer, int len)
{
   s->io.read = NULL;
   s->read_from_callbacks = 0;
   s->img_buffer = s->img_buffer_original = (stbi_uc *)buffer;
   s->img_buffer_end = s->img_buffer_original_end = (stbi_uc *)buffer + len;
}

// initialize a callback-based context
static void stbi__start_callbacks(stbi__context *s, stbi_io_callbacks *c, void *user)
{
   s->io = *c;
   s->io_user_data = user;
   s->buflen = sizeof(s->buffer_start);
   s->read_from_callbacks = 1;
   s->img_buffer_original = s->buffer_start;
   stbi__refill_buffer(s);
   s->img_buffer_original_end = s->img_buffer_end;
}

#ifndef STBI_NO_STDIO

static int stbi__stdio_read(void *user, char *data, int size)
{
   return (int)fread(data, 1, size, (FILE *)user);
}

static void stbi__stdio_skip(void *user, int n)
{
   fseek((FILE *)user, n, SEEK_CUR);
}

static int stbi__stdio_eof(void *user)
{
   return feof((FILE *)user);
}

static stbi_io_callbacks stbi__stdio_callbacks =
    {
        stbi__stdio_read,
        stbi__stdio_skip,
        stbi__stdio_eof,
};

static void stbi__start_file(stbi__context *s, FILE *f)
{
   stbi__start_callbacks(s, &stbi__stdio_callbacks, (void *)f);
}

//static void stop_file(stbi__context *s) { }

#endif // !STBI_NO_STDIO

static void stbi__rewind(stbi__context *s)
{
   // conceptually rewind SHOULD rewind to the beginning of the stream,
   // but we just rewind to the beginning of the initial buffer, because
   // we only use it after doing 'test', which only ever looks at at most 92 bytes
   s->img_buffer = s->img_buffer_original;
   s->img_buffer_end = s->img_buffer_original_end;
}

enum
{
   STBI_ORDER_RGB,
   STBI_ORDER_BGR
};

typedef struct
{
   int bits_per_channel;
   int num_channels;
   int channel_order;
} stbi__result_info;

#ifndef STBI_NO_JPEG
static int stbi__jpeg_test(stbi__context *s);
static void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp);
#endif

#ifndef STBI_NO_PNG
static int stbi__png_test(stbi__context *s);
static void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static int stbi__png_info(stbi__context *s, int *x, int *y, int *comp);
static int stbi__png_is16(stbi__context *s);
#endif

#ifndef STBI_NO_BMP
static int stbi__bmp_test(stbi__context *s);
static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static int stbi__bmp_info(stbi__context *s, int *x, int *y, int *comp);
#endif

#ifndef STBI_NO_TGA
static int stbi__tga_test(stbi__context *s);
static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static int stbi__tga_info(stbi__context *s, int *x, int *y, int *comp);
#endif

#ifndef STBI_NO_PSD
static int stbi__psd_test(stbi__context *s);
static void *stbi__psd_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc);
static int stbi__psd_info(stbi__context *s, int *x, int *y, int *comp);
static int stbi__psd_is16(stbi__context *s);
#endif

#ifndef STBI_NO_HDR
static int stbi__hdr_test(stbi__context *s);
static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static int stbi__hdr_info(stbi__context *s, int *x, int *y, int *comp);
#endif

#ifndef STBI_NO_PIC
static int stbi__pic_test(stbi__context *s);
static void *stbi__pic_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static int stbi__pic_info(stbi__context *s, int *x, int *y, int *comp);
#endif

#ifndef STBI_NO_GIF
static int stbi__gif_test(stbi__context *s);
static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp);
static int stbi__gif_info(stbi__context *s, int *x, int *y, int *comp);
#endif

#ifndef STBI_NO_PNM
static int stbi__pnm_test(stbi__context *s);
static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri);
static int stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp);
#endif

static
#ifdef STBI_THREAD_LOCAL
    STBI_THREAD_LOCAL
#endif
    const char *stbi__g_failure_reason;

STBIDEF const char *stbi_failure_reason(void)
{
   return stbi__g_failure_reason;
}

#ifndef STBI_NO_FAILURE_STRINGS
static int stbi__err(const char *str)
{
   stbi__g_failure_reason = str;
   return 0;
}
#endif

static void *stbi__malloc(size_t size)
{
   return STBI_MALLOC(size);
}

// stb_image uses ints pervasively, including for offset calculations.
// therefore the largest decoded image size we can support with the
// current code, even on 64-bit targets, is INT_MAX. this is not a
// significant limitation for the intended use case.
//
// we do, however, need to make sure our size calculations don't
// overflow. hence a few helper functions for size calculations that
// multiply integers together, making sure that they're non-negative
// and no overflow occurs.

// return 1 if the sum is valid, 0 on overflow.
// negative terms are considered invalid.
static int stbi__addsizes_valid(int a, int b)
{
   if (b < 0)
      return 0;
   // now 0 <= b <= INT_MAX, hence also
   // 0 <= INT_MAX - b <= INTMAX.
   // And "a + b <= INT_MAX" (which might overflow) is the
   // same as a <= INT_MAX - b (no overflow)
   return a <= INT_MAX - b;
}

// returns 1 if the product is valid, 0 on overflow.
// negative factors are considered invalid.
static int stbi__mul2sizes_valid(int a, int b)
{
   if (a < 0 || b < 0)
      return 0;
   if (b == 0)
      return 1; // mul-by-0 is always safe
   // portable way to check for no overflows in a*b
   return a <= INT_MAX / b;
}

#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
// returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow
static int stbi__mad2sizes_valid(int a, int b, int add)
{
   return stbi__mul2sizes_valid(a, b) && stbi__addsizes_valid(a * b, add);
}
#endif

// returns 1 if "a*b*c + add" has no negative terms/factors and doesn't overflow
static int stbi__mad3sizes_valid(int a, int b, int c, int add)
{
   return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a * b, c) &&
          stbi__addsizes_valid(a * b * c, add);
}

// returns 1 if "a*b*c*d + add" has no negative terms/factors and doesn't overflow
#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
static int stbi__mad4sizes_valid(int a, int b, int c, int d, int add)
{
   return stbi__mul2sizes_valid(a, b) && stbi__mul2sizes_valid(a * b, c) &&
          stbi__mul2sizes_valid(a * b * c, d) && stbi__addsizes_valid(a * b * c * d, add);
}
#endif

#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
// mallocs with size overflow checking
static void *stbi__malloc_mad2(int a, int b, int add)
{
   if (!stbi__mad2sizes_valid(a, b, add))
      return NULL;
   return stbi__malloc(a * b + add);
}
#endif

static void *stbi__malloc_mad3(int a, int b, int c, int add)
{
   if (!stbi__mad3sizes_valid(a, b, c, add))
      return NULL;
   return stbi__malloc(a * b * c + add);
}

#if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
static void *stbi__malloc_mad4(int a, int b, int c, int d, int add)
{
   if (!stbi__mad4sizes_valid(a, b, c, d, add))
      return NULL;
   return stbi__malloc(a * b * c * d + add);
}
#endif

// stbi__err - error
// stbi__errpf - error returning pointer to float
// stbi__errpuc - error returning pointer to unsigned char

#ifdef STBI_NO_FAILURE_STRINGS
#define stbi__err(x, y) 0
#elif defined(STBI_FAILURE_USERMSG)
#define stbi__err(x, y) stbi__err(y)
#else
#define stbi__err(x, y) stbi__err(x)
#endif

#define stbi__errpf(x, y) ((float *)(size_t)(stbi__err(x, y) ? NULL : NULL))
#define stbi__errpuc(x, y) ((unsigned char *)(size_t)(stbi__err(x, y) ? NULL : NULL))

STBIDEF void stbi_image_free(void *retval_from_stbi_load)
{
   STBI_FREE(retval_from_stbi_load);
}

#ifndef STBI_NO_LINEAR
static float *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp);
#endif

#ifndef STBI_NO_HDR
static stbi_uc *stbi__hdr_to_ldr(float *data, int x, int y, int comp);
#endif

static int stbi__vertically_flip_on_load_global = 0;

STBIDEF void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip)
{
   stbi__vertically_flip_on_load_global = flag_true_if_should_flip;
}

#ifndef STBI_THREAD_LOCAL
#define stbi__vertically_flip_on_load stbi__vertically_flip_on_load_global
#else
static STBI_THREAD_LOCAL int stbi__vertically_flip_on_load_local, stbi__vertically_flip_on_load_set;

STBIDEF void stbi_set_flip_vertically_on_load_thread(int flag_true_if_should_flip)
{
   stbi__vertically_flip_on_load_local = flag_true_if_should_flip;
   stbi__vertically_flip_on_load_set = 1;
}

#define stbi__vertically_flip_on_load (stbi__vertically_flip_on_load_set         \
                                           ? stbi__vertically_flip_on_load_local \
                                           : stbi__vertically_flip_on_load_global)
#endif // STBI_THREAD_LOCAL

static void *stbi__load_main(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
{
   memset(ri, 0, sizeof(*ri));         // make sure it's initialized if we add new fields
   ri->bits_per_channel = 8;           // default is 8 so most paths don't have to be changed
   ri->channel_order = STBI_ORDER_RGB; // all current input & output are this, but this is here so we can add BGR order
   ri->num_channels = 0;

#ifndef STBI_NO_JPEG
   if (stbi__jpeg_test(s))
      return stbi__jpeg_load(s, x, y, comp, req_comp, ri);
#endif
#ifndef STBI_NO_PNG
   if (stbi__png_test(s))
      return stbi__png_load(s, x, y, comp, req_comp, ri);
#endif
#ifndef STBI_NO_BMP
   if (stbi__bmp_test(s))
      return stbi__bmp_load(s, x, y, comp, req_comp, ri);
#endif
#ifndef STBI_NO_GIF
   if (stbi__gif_test(s))
      return stbi__gif_load(s, x, y, comp, req_comp, ri);
#endif
#ifndef STBI_NO_PSD
   if (stbi__psd_test(s))
      return stbi__psd_load(s, x, y, comp, req_comp, ri, bpc);
#else
   STBI_NOTUSED(bpc);
#endif
#ifndef STBI_NO_PIC
   if (stbi__pic_test(s))
      return stbi__pic_load(s, x, y, comp, req_comp, ri);
#endif
#ifndef STBI_NO_PNM
   if (stbi__pnm_test(s))
      return stbi__pnm_load(s, x, y, comp, req_comp, ri);
#endif

#ifndef STBI_NO_HDR
   if (stbi__hdr_test(s))
   {
      float *hdr = stbi__hdr_load(s, x, y, comp, req_comp, ri);
      return stbi__hdr_to_ldr(hdr, *x, *y, req_comp ? req_comp : *comp);
   }
#endif

#ifndef STBI_NO_TGA
   // test tga last because it's a crappy test!
   if (stbi__tga_test(s))
      return stbi__tga_load(s, x, y, comp, req_comp, ri);
#endif

   return stbi__errpuc("unknown image type", "Image not of any known type, or corrupt");
}

static stbi_uc *stbi__convert_16_to_8(stbi__uint16 *orig, int w, int h, int channels)
{
   int i;
   int img_len = w * h * channels;
   stbi_uc *reduced;

   reduced = (stbi_uc *)stbi__malloc(img_len);
   if (reduced == NULL)
      return stbi__errpuc("outofmem", "Out of memory");

   for (i = 0; i < img_len; ++i)
      reduced[i] = (stbi_uc)((orig[i] >> 8) & 0xFF); // top half of each byte is sufficient approx of 16->8 bit scaling

   STBI_FREE(orig);
   return reduced;
}

static stbi__uint16 *stbi__convert_8_to_16(stbi_uc *orig, int w, int h, int channels)
{
   int i;
   int img_len = w * h * channels;
   stbi__uint16 *enlarged;

   enlarged = (stbi__uint16 *)stbi__malloc(img_len * 2);
   if (enlarged == NULL)
      return (stbi__uint16 *)stbi__errpuc("outofmem", "Out of memory");

   for (i = 0; i < img_len; ++i)
      enlarged[i] = (stbi__uint16)((orig[i] << 8) + orig[i]); // replicate to high and low byte, maps 0->0, 255->0xffff

   STBI_FREE(orig);
   return enlarged;
}

static void stbi__vertical_flip(void *image, int w, int h, int bytes_per_pixel)
{
   int row;
   size_t bytes_per_row = (size_t)w * bytes_per_pixel;
   stbi_uc temp[2048];
   stbi_uc *bytes = (stbi_uc *)image;

   for (row = 0; row < (h >> 1); row++)
   {
      stbi_uc *row0 = bytes + row * bytes_per_row;
      stbi_uc *row1 = bytes + (h - row - 1) * bytes_per_row;
      // swap row0 with row1
      size_t bytes_left = bytes_per_row;
      while (bytes_left)
      {
         size_t bytes_copy = (bytes_left < sizeof(temp)) ? bytes_left : sizeof(temp);
         memcpy(temp, row0, bytes_copy);
         memcpy(row0, row1, bytes_copy);
         memcpy(row1, temp, bytes_copy);
         row0 += bytes_copy;
         row1 += bytes_copy;
         bytes_left -= bytes_copy;
      }
   }
}

#ifndef STBI_NO_GIF
static void stbi__vertical_flip_slices(void *image, int w, int h, int z, int bytes_per_pixel)
{
   int slice;
   int slice_size = w * h * bytes_per_pixel;

   stbi_uc *bytes = (stbi_uc *)image;
   for (slice = 0; slice < z; ++slice)
   {
      stbi__vertical_flip(bytes, w, h, bytes_per_pixel);
      bytes += slice_size;
   }
}
#endif

static unsigned char *stbi__load_and_postprocess_8bit(stbi__context *s, int *x, int *y, int *comp, int req_comp)
{
   stbi__result_info ri;
   void *result = stbi__load_main(s, x, y, comp, req_comp, &ri, 8);

   if (result == NULL)
      return NULL;

   if (ri.bits_per_channel != 8)
   {
      STBI_ASSERT(ri.bits_per_channel == 16);
      result = stbi__convert_16_to_8((stbi__uint16 *)result, *x, *y, req_comp == 0 ? *comp : req_comp);
      ri.bits_per_channel = 8;
   }

   // @TODO: move stbi__convert_format to here

   if (stbi__vertically_flip_on_load)
   {
      int channels = req_comp ? req_comp : *comp;
      stbi__vertical_flip(result, *x, *y, channels * sizeof(stbi_uc));
   }

   return (unsigned char *)result;
}

static stbi__uint16 *stbi__load_and_postprocess_16bit(stbi__context *s, int *x, int *y, int *comp, int req_comp)
{
   stbi__result_info ri;
   void *result = stbi__load_main(s, x, y, comp, req_comp, &ri, 16);

   if (result == NULL)
      return NULL;

   if (ri.bits_per_channel != 16)
   {
      STBI_ASSERT(ri.bits_per_channel == 8);
      result = stbi__convert_8_to_16((stbi_uc *)result, *x, *y, req_comp == 0 ? *comp : req_comp);
      ri.bits_per_channel = 16;
   }

   // @TODO: move stbi__convert_format16 to here
   // @TODO: special case RGB-to-Y (and RGBA-to-YA) for 8-bit-to-16-bit case to keep more precision

   if (stbi__vertically_flip_on_load)
   {
      int channels = req_comp ? req_comp : *comp;
      stbi__vertical_flip(result, *x, *y, channels * sizeof(stbi__uint16));
   }

   return (stbi__uint16 *)result;
}

#if !defined(STBI_NO_HDR) && !defined(STBI_NO_LINEAR)
static void stbi__float_postprocess(float *result, int *x, int *y, int *comp, int req_comp)
{
   if (stbi__vertically_flip_on_load && result != NULL)
   {
      int channels = req_comp ? req_comp : *comp;
      stbi__vertical_flip(result, *x, *y, channels * sizeof(float));
   }
}
#endif

#ifndef STBI_NO_STDIO

#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
STBI_EXTERN __declspec(dllimport) int __stdcall MultiByteToWideChar(unsigned int cp, unsigned long flags, const char *str, int cbmb, wchar_t *widestr, int cchwide);
STBI_EXTERN __declspec(dllimport) int __stdcall WideCharToMultiByte(unsigned int cp, unsigned long flags, const wchar_t *widestr, int cchwide, char *str, int cbmb, const char *defchar, int *used_default);
#endif

#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
STBIDEF int stbi_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t *input)
{
   return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int)bufferlen, NULL, NULL);
}
#endif

static FILE *stbi__fopen(char const *filename, char const *mode)
{
   FILE *f;
#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
   wchar_t wMode[64];
   wchar_t wFilename[1024];
   if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)))
      return 0;

   if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)))
      return 0;

#if _MSC_VER >= 1400
   if (0 != _wfopen_s(&f, wFilename, wMode))
      f = 0;
#else
   f = _wfopen(wFilename, wMode);
#endif

#elif defined(_MSC_VER) && _MSC_VER >= 1400
   if (0 != fopen_s(&f, filename, mode))
      f = 0;
#else
   f = fopen(filename, mode);
#endif
   return f;
}

STBIDEF stbi_uc *stbi_load(char const *filename, int *x, int *y, int *comp, int req_comp)
{
   FILE *f = stbi__fopen(filename, "rb");
   unsigned char *result;
   if (!f)
      return stbi__errpuc("can't fopen", "Unable to open file");
   result = stbi_load_from_file(f, x, y, comp, req_comp);
   fclose(f);
   return result;
}

STBIDEF stbi_uc *stbi_load_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
{
   unsigned char *result;
   stbi__context s;
   stbi__start_file(&s, f);
   result = stbi__load_and_postprocess_8bit(&s, x, y, comp, req_comp);
   if (result)
   {
      // need to 'unget' all the characters in the IO buffer
      fseek(f, -(int)(s.img_buffer_end - s.img_buffer), SEEK_CUR);
   }
   return result;
}

STBIDEF stbi__uint16 *stbi_load_from_file_16(FILE *f, int *x, int *y, int *comp, int req_comp)
{
   stbi__uint16 *result;
   stbi__context s;
   stbi__start_file(&s, f);
   result = stbi__load_and_postprocess_16bit(&s, x, y, comp, req_comp);
   if (result)
   {
      // need to 'unget' all the characters in the IO buffer
      fseek(f, -(int)(s.img_buffer_end - s.img_buffer), SEEK_CUR);
   }
   return result;
}

STBIDEF stbi_us *stbi_load_16(char const *filename, int *x, int *y, int *comp, int req_comp)
{
   FILE *f = stbi__fopen(filename, "rb");
   stbi__uint16 *result;
   if (!f)
      return (stbi_us *)stbi__errpuc("can't fopen", "Unable to open file");
   result = stbi_load_from_file_16(f, x, y, comp, req_comp);
   fclose(f);
   return result;
}

#endif //!STBI_NO_STDIO

STBIDEF stbi_us *stbi_load_16_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *channels_in_file, int desired_channels)
{
   stbi__context s;
   stbi__start_mem(&s, buffer, len);
   return stbi__load_and_postprocess_16bit(&s, x, y, channels_in_file, desired_channels);
}

STBIDEF stbi_us *stbi_load_16_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *channels_in_file, int desired_channels)
{
   stbi__context s;
   stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user);
   return stbi__load_and_postprocess_16bit(&s, x, y, channels_in_file, desired_channels);
}

STBIDEF stbi_uc *stbi_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
{
   stbi__context s;
   stbi__start_mem(&s, buffer, len);
   return stbi__load_and_postprocess_8bit(&s, x, y, comp, req_comp);
}

STBIDEF stbi_uc *stbi_load_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
{
   stbi__context s;
   stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user);
   return stbi__load_and_postprocess_8bit(&s, x, y, comp, req_comp);
}

#ifndef STBI_NO_GIF
STBIDEF stbi_uc *stbi_load_gif_from_memory(stbi_uc const *buffer, int len, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
{
   unsigned char *result;
   stbi__context s;
   stbi__start_mem(&s, buffer, len);

   result = (unsigned char *)stbi__load_gif_main(&s, delays, x, y, z, comp, req_comp);
   if (stbi__vertically_flip_on_load)
   {
      stbi__vertical_flip_slices(result, *x, *y, *z, *comp);
   }

   return result;
}
#endif

#ifndef STBI_NO_LINEAR
static float *stbi__loadf_main(stbi__context *s, int *x, int *y, int *comp, int req_comp)
{
   unsigned char *data;
#ifndef STBI_NO_HDR
   if (stbi__hdr_test(s))
   {
      stbi__result_info ri;
      float *hdr_data = stbi__hdr_load(s, x, y, comp, req_comp, &ri);
      if (hdr_data)
         stbi__float_postprocess(hdr_data, x, y, comp, req_comp);
      return hdr_data;
   }
#endif
   data = stbi__load_and_postprocess_8bit(s, x, y, comp, req_comp);
   if (data)
      return stbi__ldr_to_hdr(data, *x, *y, req_comp ? req_comp : *comp);
   return stbi__errpf("unknown image type", "Image not of any known type, or corrupt");
}

STBIDEF float *stbi_loadf_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
{
   stbi__context s;
   stbi__start_mem(&s, buffer, len);
   return stbi__loadf_main(&s, x, y, comp, req_comp);
}

STBIDEF float *stbi_loadf_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp, int req_comp)
{
   stbi__context s;
   stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user);
   return stbi__loadf_main(&s, x, y, comp, req_comp);
}

#ifndef STBI_NO_STDIO
STBIDEF float *stbi_loadf(char const *filename, int *x, int *y, int *comp, int req_comp)
{
   float *result;
   FILE *f = stbi__fopen(filename, "rb");
   if (!f)
      return stbi__errpf("can't fopen", "Unable to open file");
   result = stbi_loadf_from_file(f, x, y, comp, req_comp);
   fclose(f);
   return result;
}

STBIDEF float *stbi_loadf_from_file(FILE *f, int *x, int *y, int *comp, int req_comp)
{
   stbi__context s;
   stbi__start_file(&s, f);
   return stbi__loadf_main(&s, x, y, comp, req_comp);
}
#endif // !STBI_NO_STDIO

#endif // !STBI_NO_LINEAR

// these is-hdr-or-not is defined independent of whether STBI_NO_LINEAR is
// defined, for API simplicity; if STBI_NO_LINEAR is defined, it always
// reports false!

STBIDEF int stbi_is_hdr_from_memory(stbi_uc const *buffer, int len)
{
#ifndef STBI_NO_HDR
   stbi__context s;
   stbi__start_mem(&s, buffer, len);
   return stbi__hdr_test(&s);
#else
   STBI_NOTUSED(buffer);
   STBI_NOTUSED(len);
   return 0;
#endif
}

#ifndef STBI_NO_STDIO
STBIDEF int stbi_is_hdr(char const *filename)
{
   FILE *f = stbi__fopen(filename, "rb");
   int result = 0;
   if (f)
   {
      result = stbi_is_hdr_from_file(f);
      fclose(f);
   }
   return result;
}

STBIDEF int stbi_is_hdr_from_file(FILE *f)
{
#ifndef STBI_NO_HDR
   long pos = ftell(f);
   int res;
   stbi__context s;
   stbi__start_file(&s, f);
   res = stbi__hdr_test(&s);
   fseek(f, pos, SEEK_SET);
   return res;
#else
   STBI_NOTUSED(f);
   return 0;
#endif
}
#endif // !STBI_NO_STDIO

STBIDEF int stbi_is_hdr_from_callbacks(stbi_io_callbacks const *clbk, void *user)
{
#ifndef STBI_NO_HDR
   stbi__context s;
   stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user);
   return stbi__hdr_test(&s);
#else
   STBI_NOTUSED(clbk);
   STBI_NOTUSED(user);
   return 0;
#endif
}

#ifndef STBI_NO_LINEAR
static float stbi__l2h_gamma = 2.2f, stbi__l2h_scale = 1.0f;

STBIDEF void stbi_ldr_to_hdr_gamma(float gamma) { stbi__l2h_gamma = gamma; }
STBIDEF void stbi_ldr_to_hdr_scale(float scale) { stbi__l2h_scale = scale; }
#endif

static float stbi__h2l_gamma_i = 1.0f / 2.2f, stbi__h2l_scale_i = 1.0f;

STBIDEF void stbi_hdr_to_ldr_gamma(float gamma) { stbi__h2l_gamma_i = 1 / gamma; }
STBIDEF void stbi_hdr_to_ldr_scale(float scale) { stbi__h2l_scale_i = 1 / scale; }

//////////////////////////////////////////////////////////////////////////////
//
// Common code used by all image loaders
//

enum
{
   STBI__SCAN_load = 0,
   STBI__SCAN_type,
   STBI__SCAN_header
};

static void stbi__refill_buffer(stbi__context *s)
{
   int n = (s->io.read)(s->io_user_data, (char *)s->buffer_start, s->buflen);
   if (n == 0)
   {
      // at end of file, treat same as if from memory, but need to handle case
      // where s->img_buffer isn't pointing to safe memory, e.g. 0-byte file
      s->read_from_callbacks = 0;
      s->img_buffer = s->buffer_start;
      s->img_buffer_end = s->buffer_start + 1;
      *s->img_buffer = 0;
   }
   else
   {
      s->img_buffer = s->buffer_start;
      s->img_buffer_end = s->buffer_start + n;
   }
}

stbi_inline static stbi_uc stbi__get8(stbi__context *s)
{
   if (s->img_buffer < s->img_buffer_end)
      return *s->img_buffer++;
   if (s->read_from_callbacks)
   {
      stbi__refill_buffer(s);
      return *s->img_buffer++;
   }
   return 0;
}

#if defined(STBI_NO_JPEG) && defined(STBI_NO_HDR) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
// nothing
#else
stbi_inline static int stbi__at_eof(stbi__context *s)
{
   if (s->io.read)
   {
      if (!(s->io.eof)(s->io_user_data))
         return 0;
      // if feof() is true, check if buffer = end
      // special case: we've only got the special 0 character at the end
      if (s->read_from_callbacks == 0)
         return 1;
   }

   return s->img_buffer >= s->img_buffer_end;
}
#endif

#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC)
// nothing
#else
static void stbi__skip(stbi__context *s, int n)
{
   if (n < 0)
   {
      s->img_buffer = s->img_buffer_end;
      return;
   }
   if (s->io.read)
   {
      int blen = (int)(s->img_buffer_end - s->img_buffer);
      if (blen < n)
      {
         s->img_buffer = s->img_buffer_end;
         (s->io.skip)(s->io_user_data, n - blen);
         return;
      }
   }
   s->img_buffer += n;
}
#endif

#if defined(STBI_NO_PNG) && defined(STBI_NO_TGA) && defined(STBI_NO_HDR) && defined(STBI_NO_PNM)
// nothing
#else
static int stbi__getn(stbi__context *s, stbi_uc *buffer, int n)
{
   if (s->io.read)
   {
      int blen = (int)(s->img_buffer_end - s->img_buffer);
      if (blen < n)
      {
         int res, count;

         memcpy(buffer, s->img_buffer, blen);

         count = (s->io.read)(s->io_user_data, (char *)buffer + blen, n - blen);
         res = (count == (n - blen));
         s->img_buffer = s->img_buffer_end;
         return res;
      }
   }

   if (s->img_buffer + n <= s->img_buffer_end)
   {
      memcpy(buffer, s->img_buffer, n);
      s->img_buffer += n;
      return 1;
   }
   else
      return 0;
}
#endif

#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
// nothing
#else
static int stbi__get16be(stbi__context *s)
{
   int z = stbi__get8(s);
   return (z << 8) + stbi__get8(s);
}
#endif

#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
// nothing
#else
static stbi__uint32 stbi__get32be(stbi__context *s)
{
   stbi__uint32 z = stbi__get16be(s);
   return (z << 16) + stbi__get16be(s);
}
#endif

#if defined(STBI_NO_BMP) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF)
// nothing
#else
static int stbi__get16le(stbi__context *s)
{
   int z = stbi__get8(s);
   return z + (stbi__get8(s) << 8);
}
#endif

#ifndef STBI_NO_BMP
static stbi__uint32 stbi__get32le(stbi__context *s)
{
   stbi__uint32 z = stbi__get16le(s);
   return z + (stbi__get16le(s) << 16);
}
#endif

#define STBI__BYTECAST(x) ((stbi_uc)((x)&255)) // truncate int to byte without warnings

#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
// nothing
#else
//////////////////////////////////////////////////////////////////////////////
//
//  generic converter from built-in img_n to req_comp
//    individual types do this automatically as much as possible (e.g. jpeg
//    does all cases internally since it needs to colorspace convert anyway,
//    and it never has alpha, so very few cases ). png can automatically
//    interleave an alpha=255 channel, but falls back to this for other cases
//
//  assume data buffer is malloced, so malloc a new one and free that one
//  only failure mode is malloc failing

static stbi_uc stbi__compute_y(int r, int g, int b)
{
   return (stbi_uc)(((r * 77) + (g * 150) + (29 * b)) >> 8);
}
#endif

#if defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
// nothing
#else
static unsigned char *stbi__convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y)
{
   int i, j;
   unsigned char *good;

   if (req_comp == img_n)
      return data;
   STBI_ASSERT(req_comp >= 1 && req_comp <= 4);

   good = (unsigned char *)stbi__malloc_mad3(req_comp, x, y, 0);
   if (good == NULL)
   {
      STBI_FREE(data);
      return stbi__errpuc("outofmem", "Out of memory");
   }

   for (j = 0; j < (int)y; ++j)
   {
      unsigned char *src = data + j * x * img_n;
      unsigned char *dest = good + j * x * req_comp;

#define STBI__COMBO(a, b) ((a)*8 + (b))
#define STBI__CASE(a, b)   \
   case STBI__COMBO(a, b): \
      for (i = x - 1; i >= 0; --i, src += a, dest += b)
      // convert source image with img_n components to one with req_comp components;
      // avoid switch per pixel, so use switch per scanline and massive macros
      switch (STBI__COMBO(img_n, req_comp))
      {
         STBI__CASE(1, 2)
         {
            dest[0] = src[0];
            dest[1] = 255;
         }
         break;
         STBI__CASE(1, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
         break;
         STBI__CASE(1, 4)
         {
            dest[0] = dest[1] = dest[2] = src[0];
            dest[3] = 255;
         }
         break;
         STBI__CASE(2, 1) { dest[0] = src[0]; }
         break;
         STBI__CASE(2, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
         break;
         STBI__CASE(2, 4)
         {
            dest[0] = dest[1] = dest[2] = src[0];
            dest[3] = src[1];
         }
         break;
         STBI__CASE(3, 4)
         {
            dest[0] = src[0];
            dest[1] = src[1];
            dest[2] = src[2];
            dest[3] = 255;
         }
         break;
         STBI__CASE(3, 1) { dest[0] = stbi__compute_y(src[0], src[1], src[2]); }
         break;
         STBI__CASE(3, 2)
         {
            dest[0] = stbi__compute_y(src[0], src[1], src[2]);
            dest[1] = 255;
         }
         break;
         STBI__CASE(4, 1) { dest[0] = stbi__compute_y(src[0], src[1], src[2]); }
         break;
         STBI__CASE(4, 2)
         {
            dest[0] = stbi__compute_y(src[0], src[1], src[2]);
            dest[1] = src[3];
         }
         break;
         STBI__CASE(4, 3)
         {
            dest[0] = src[0];
            dest[1] = src[1];
            dest[2] = src[2];
         }
         break;
      default:
         STBI_ASSERT(0);
      }
#undef STBI__CASE
   }

   STBI_FREE(data);
   return good;
}
#endif

#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
// nothing
#else
static stbi__uint16 stbi__compute_y_16(int r, int g, int b)
{
   return (stbi__uint16)(((r * 77) + (g * 150) + (29 * b)) >> 8);
}
#endif

#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
// nothing
#else
static stbi__uint16 *stbi__convert_format16(stbi__uint16 *data, int img_n, int req_comp, unsigned int x, unsigned int y)
{
   int i, j;
   stbi__uint16 *good;

   if (req_comp == img_n)
      return data;
   STBI_ASSERT(req_comp >= 1 && req_comp <= 4);

   good = (stbi__uint16 *)stbi__malloc(req_comp * x * y * 2);
   if (good == NULL)
   {
      STBI_FREE(data);
      return (stbi__uint16 *)stbi__errpuc("outofmem", "Out of memory");
   }

   for (j = 0; j < (int)y; ++j)
   {
      stbi__uint16 *src = data + j * x * img_n;
      stbi__uint16 *dest = good + j * x * req_comp;

#define STBI__COMBO(a, b) ((a)*8 + (b))
#define STBI__CASE(a, b)   \
   case STBI__COMBO(a, b): \
      for (i = x - 1; i >= 0; --i, src += a, dest += b)
      // convert source image with img_n components to one with req_comp components;
      // avoid switch per pixel, so use switch per scanline and massive macros
      switch (STBI__COMBO(img_n, req_comp))
      {
         STBI__CASE(1, 2)
         {
            dest[0] = src[0];
            dest[1] = 0xffff;
         }
         break;
         STBI__CASE(1, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
         break;
         STBI__CASE(1, 4)
         {
            dest[0] = dest[1] = dest[2] = src[0];
            dest[3] = 0xffff;
         }
         break;
         STBI__CASE(2, 1) { dest[0] = src[0]; }
         break;
         STBI__CASE(2, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
         break;
         STBI__CASE(2, 4)
         {
            dest[0] = dest[1] = dest[2] = src[0];
            dest[3] = src[1];
         }
         break;
         STBI__CASE(3, 4)
         {
            dest[0] = src[0];
            dest[1] = src[1];
            dest[2] = src[2];
            dest[3] = 0xffff;
         }
         break;
         STBI__CASE(3, 1) { dest[0] = stbi__compute_y_16(src[0], src[1], src[2]); }
         break;
         STBI__CASE(3, 2)
         {
            dest[0] = stbi__compute_y_16(src[0], src[1], src[2]);
            dest[1] = 0xffff;
         }
         break;
         STBI__CASE(4, 1) { dest[0] = stbi__compute_y_16(src[0], src[1], src[2]); }
         break;
         STBI__CASE(4, 2)
         {
            dest[0] = stbi__compute_y_16(src[0], src[1], src[2]);
            dest[1] = src[3];
         }
         break;
         STBI__CASE(4, 3)
         {
            dest[0] = src[0];
            dest[1] = src[1];
            dest[2] = src[2];
         }
         break;
      default:
         STBI_ASSERT(0);
      }
#undef STBI__CASE
   }

   STBI_FREE(data);
   return good;
}
#endif

#ifndef STBI_NO_LINEAR
static float *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp)
{
   int i, k, n;
   float *output;
   if (!data)
      return NULL;
   output = (float *)stbi__malloc_mad4(x, y, comp, sizeof(float), 0);
   if (output == NULL)
   {
      STBI_FREE(data);
      return stbi__errpf("outofmem", "Out of memory");
   }
   // compute number of non-alpha components
   if (comp & 1)
      n = comp;
   else
      n = comp - 1;
   for (i = 0; i < x * y; ++i)
   {
      for (k = 0; k < n; ++k)
      {
         output[i * comp + k] = (float)(pow(data[i * comp + k] / 255.0f, stbi__l2h_gamma) * stbi__l2h_scale);
      }
   }
   if (n < comp)
   {
      for (i = 0; i < x * y; ++i)
      {
         output[i * comp + n] = data[i * comp + n] / 255.0f;
      }
   }
   STBI_FREE(data);
   return output;
}
#endif

#ifndef STBI_NO_HDR
#define stbi__float2int(x) ((int)(x))
static stbi_uc *stbi__hdr_to_ldr(float *data, int x, int y, int comp)
{
   int i, k, n;
   stbi_uc *output;
   if (!data)
      return NULL;
   output = (stbi_uc *)stbi__malloc_mad3(x, y, comp, 0);
   if (output == NULL)
   {
      STBI_FREE(data);
      return stbi__errpuc("outofmem", "Out of memory");
   }
   // compute number of non-alpha components
   if (comp & 1)
      n = comp;
   else
      n = comp - 1;
   for (i = 0; i < x * y; ++i)
   {
      for (k = 0; k < n; ++k)
      {
         float z = (float)pow(data[i * comp + k] * stbi__h2l_scale_i, stbi__h2l_gamma_i) * 255 + 0.5f;
         if (z < 0)
            z = 0;
         if (z > 255)
            z = 255;
         output[i * comp + k] = (stbi_uc)stbi__float2int(z);
      }
      if (k < comp)
      {
         float z = data[i * comp + k] * 255 + 0.5f;
         if (z < 0)
            z = 0;
         if (z > 255)
            z = 255;
         output[i * comp + k] = (stbi_uc)stbi__float2int(z);
      }
   }
   STBI_FREE(data);
   return output;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//  "baseline" JPEG/JFIF decoder
//
//    simple implementation
//      - doesn't support delayed output of y-dimension
//      - simple interface (only one output format: 8-bit interleaved RGB)
//      - doesn't try to recover corrupt jpegs
//      - doesn't allow partial loading, loading multiple at once
//      - still fast on x86 (copying globals into locals doesn't help x86)
//      - allocates lots of intermediate memory (full size of all components)
//        - non-interleaved case requires this anyway
//        - allows good upsampling (see next)
//    high-quality
//      - upsampled channels are bilinearly interpolated, even across blocks
//      - quality integer IDCT derived from IJG's 'slow'
//    performance
//      - fast huffman; reasonable integer IDCT
//      - some SIMD kernels for common paths on targets with SSE2/NEON
//      - uses a lot of intermediate memory, could cache poorly

#ifndef STBI_NO_JPEG

// huffman decoding acceleration
#define FAST_BITS 9 // larger handles more cases; smaller stomps less cache

typedef struct
{
   stbi_uc fast[1 << FAST_BITS];
   // weirdly, repacking this into AoS is a 10% speed loss, instead of a win
   stbi__uint16 code[256];
   stbi_uc values[256];
   stbi_uc size[257];
   unsigned int maxcode[18];
   int delta[17]; // old 'firstsymbol' - old 'firstcode'
} stbi__huffman;

typedef struct
{
   stbi__context *s;
   stbi__huffman huff_dc[4];
   stbi__huffman huff_ac[4];
   stbi__uint16 dequant[4][64];
   stbi__int16 fast_ac[4][1 << FAST_BITS];

   // sizes for components, interleaved MCUs
   int img_h_max, img_v_max;
   int img_mcu_x, img_mcu_y;
   int img_mcu_w, img_mcu_h;

   // definition of jpeg image component
   struct
   {
      int id;
      int h, v;
      int tq;
      int hd, ha;
      int dc_pred;

      int x, y, w2, h2;
      stbi_uc *data;
      void *raw_data, *raw_coeff;
      stbi_uc *linebuf;
      short *coeff;         // progressive only
      int coeff_w, coeff_h; // number of 8x8 coefficient blocks
   } img_comp[4];

   stbi__uint32 code_buffer; // jpeg entropy-coded buffer
   int code_bits;            // number of valid bits
   unsigned char marker;     // marker seen while filling entropy buffer
   int nomore;               // flag if we saw a marker so must stop

   int progressive;
   int spec_start;
   int spec_end;
   int succ_high;
   int succ_low;
   int eob_run;
   int jfif;
   int app14_color_transform; // Adobe APP14 tag
   int rgb;

   int scan_n, order[4];
   int restart_interval, todo;

   // kernels
   void (*idct_block_kernel)(stbi_uc *out, int out_stride, short data[64]);
   void (*YCbCr_to_RGB_kernel)(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step);
   stbi_uc *(*resample_row_hv_2_kernel)(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs);
} stbi__jpeg;

static int stbi__build_huffman(stbi__huffman *h, int *count)
{
   int i, j, k = 0;
   unsigned int code;
   // build size list for each symbol (from JPEG spec)
   for (i = 0; i < 16; ++i)
      for (j = 0; j < count[i]; ++j)
         h->size[k++] = (stbi_uc)(i + 1);
   h->size[k] = 0;

   // compute actual symbols (from jpeg spec)
   code = 0;
   k = 0;
   for (j = 1; j <= 16; ++j)
   {
      // compute delta to add to code to compute symbol id
      h->delta[j] = k - code;
      if (h->size[k] == j)
      {
         while (h->size[k] == j)
            h->code[k++] = (stbi__uint16)(code++);
         if (code - 1 >= (1u << j))
            return stbi__err("bad code lengths", "Corrupt JPEG");
      }
      // compute largest code + 1 for this size, preshifted as needed later
      h->maxcode[j] = code << (16 - j);
      code <<= 1;
   }
   h->maxcode[j] = 0xffffffff;

   // build non-spec acceleration table; 255 is flag for not-accelerated
   memset(h->fast, 255, 1 << FAST_BITS);
   for (i = 0; i < k; ++i)
   {
      int s = h->size[i];
      if (s <= FAST_BITS)
      {
         int c = h->code[i] << (FAST_BITS - s);
         int m = 1 << (FAST_BITS - s);
         for (j = 0; j < m; ++j)
         {
            h->fast[c + j] = (stbi_uc)i;
         }
      }
   }
   return 1;
}

// build a table that decodes both magnitude and value of small ACs in
// one go.
static void stbi__build_fast_ac(stbi__int16 *fast_ac, stbi__huffman *h)
{
   int i;
   for (i = 0; i < (1 << FAST_BITS); ++i)
   {
      stbi_uc fast = h->fast[i];
      fast_ac[i] = 0;
      if (fast < 255)
      {
         int rs = h->values[fast];
         int run = (rs >> 4) & 15;
         int magbits = rs & 15;
         int len = h->size[fast];

         if (magbits && len + magbits <= FAST_BITS)
         {
            // magnitude code followed by receive_extend code
            int k = ((i << len) & ((1 << FAST_BITS) - 1)) >> (FAST_BITS - magbits);
            int m = 1 << (magbits - 1);
            if (k < m)
               k += (~0U << magbits) + 1;
            // if the result is small enough, we can fit it in fast_ac table
            if (k >= -128 && k <= 127)
               fast_ac[i] = (stbi__int16)((k * 256) + (run * 16) + (len + magbits));
         }
      }
   }
}

static void stbi__grow_buffer_unsafe(stbi__jpeg *j)
{
   do
   {
      unsigned int b = j->nomore ? 0 : stbi__get8(j->s);
      if (b == 0xff)
      {
         int c = stbi__get8(j->s);
         while (c == 0xff)
            c = stbi__get8(j->s); // consume fill bytes
         if (c != 0)
         {
            j->marker = (unsigned char)c;
            j->nomore = 1;
            return;
         }
      }
      j->code_buffer |= b << (24 - j->code_bits);
      j->code_bits += 8;
   } while (j->code_bits <= 24);
}

// (1 << n) - 1
static const stbi__uint32 stbi__bmask[17] = {0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535};

// decode a jpeg huffman value from the bitstream
stbi_inline static int stbi__jpeg_huff_decode(stbi__jpeg *j, stbi__huffman *h)
{
   unsigned int temp;
   int c, k;

   if (j->code_bits < 16)
      stbi__grow_buffer_unsafe(j);

   // look at the top FAST_BITS and determine what symbol ID it is,
   // if the code is <= FAST_BITS
   c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS) - 1);
   k = h->fast[c];
   if (k < 255)
   {
      int s = h->size[k];
      if (s > j->code_bits)
         return -1;
      j->code_buffer <<= s;
      j->code_bits -= s;
      return h->values[k];
   }

   // naive test is to shift the code_buffer down so k bits are
   // valid, then test against maxcode. To speed this up, we've
   // preshifted maxcode left so that it has (16-k) 0s at the
   // end; in other words, regardless of the number of bits, it
   // wants to be compared against something shifted to have 16;
   // that way we don't need to shift inside the loop.
   temp = j->code_buffer >> 16;
   for (k = FAST_BITS + 1;; ++k)
      if (temp < h->maxcode[k])
         break;
   if (k == 17)
   {
      // error! code not found
      j->code_bits -= 16;
      return -1;
   }

   if (k > j->code_bits)
      return -1;

   // convert the huffman code to the symbol id
   c = ((j->code_buffer >> (32 - k)) & stbi__bmask[k]) + h->delta[k];
   STBI_ASSERT((((j->code_buffer) >> (32 - h->size[c])) & stbi__bmask[h->size[c]]) == h->code[c]);

   // convert the id to a symbol
   j->code_bits -= k;
   j->code_buffer <<= k;
   return h->values[c];
}

// bias[n] = (-1<<n) + 1
static const int stbi__jbias[16] = {0, -1, -3, -7, -15, -31, -63, -127, -255, -511, -1023, -2047, -4095, -8191, -16383, -32767};

// combined JPEG 'receive' and JPEG 'extend', since baseline
// always extends everything it receives.
stbi_inline static int stbi__extend_receive(stbi__jpeg *j, int n)
{
   unsigned int k;
   int sgn;
   if (j->code_bits < n)
      stbi__grow_buffer_unsafe(j);

   sgn = (stbi__int32)j->code_buffer >> 31; // sign bit is always in MSB
   k = stbi_lrot(j->code_buffer, n);
   STBI_ASSERT(n >= 0 && n < (int)(sizeof(stbi__bmask) / sizeof(*stbi__bmask)));
   j->code_buffer = k & ~stbi__bmask[n];
   k &= stbi__bmask[n];
   j->code_bits -= n;
   return k + (stbi__jbias[n] & ~sgn);
}

// get some unsigned bits
stbi_inline static int stbi__jpeg_get_bits(stbi__jpeg *j, int n)
{
   unsigned int k;
   if (j->code_bits < n)
      stbi__grow_buffer_unsafe(j);
   k = stbi_lrot(j->code_buffer, n);
   j->code_buffer = k & ~stbi__bmask[n];
   k &= stbi__bmask[n];
   j->code_bits -= n;
   return k;
}

stbi_inline static int stbi__jpeg_get_bit(stbi__jpeg *j)
{
   unsigned int k;
   if (j->code_bits < 1)
      stbi__grow_buffer_unsafe(j);
   k = j->code_buffer;
   j->code_buffer <<= 1;
   --j->code_bits;
   return k & 0x80000000;
}

// given a value that's at position X in the zigzag stream,
// where does it appear in the 8x8 matrix coded as row-major?
static const stbi_uc stbi__jpeg_dezigzag[64 + 15] =
    {
        0, 1, 8, 16, 9, 2, 3, 10,
        17, 24, 32, 25, 18, 11, 4, 5,
        12, 19, 26, 33, 40, 48, 41, 34,
        27, 20, 13, 6, 7, 14, 21, 28,
        35, 42, 49, 56, 57, 50, 43, 36,
        29, 22, 15, 23, 30, 37, 44, 51,
        58, 59, 52, 45, 38, 31, 39, 46,
        53, 60, 61, 54, 47, 55, 62, 63,
        // let corrupt input sample past end
        63, 63, 63, 63, 63, 63, 63, 63,
        63, 63, 63, 63, 63, 63, 63};

// decode one 64-entry block--
static int stbi__jpeg_decode_block(stbi__jpeg *j, short data[64], stbi__huffman *hdc, stbi__huffman *hac, stbi__int16 *fac, int b, stbi__uint16 *dequant)
{
   int diff, dc, k;
   int t;

   if (j->code_bits < 16)
      stbi__grow_buffer_unsafe(j);
   t = stbi__jpeg_huff_decode(j, hdc);
   if (t < 0)
      return stbi__err("bad huffman code", "Corrupt JPEG");

   // 0 all the ac values now so we can do it 32-bits at a time
   memset(data, 0, 64 * sizeof(data[0]));

   diff = t ? stbi__extend_receive(j, t) : 0;
   dc = j->img_comp[b].dc_pred + diff;
   j->img_comp[b].dc_pred = dc;
   data[0] = (short)(dc * dequant[0]);

   // decode AC components, see JPEG spec
   k = 1;
   do
   {
      unsigned int zig;
      int c, r, s;
      if (j->code_bits < 16)
         stbi__grow_buffer_unsafe(j);
      c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS) - 1);
      r = fac[c];
      if (r)
      {                      // fast-AC path
         k += (r >> 4) & 15; // run
         s = r & 15;         // combined length
         j->code_buffer <<= s;
         j->code_bits -= s;
         // decode into unzigzag'd location
         zig = stbi__jpeg_dezigzag[k++];
         data[zig] = (short)((r >> 8) * dequant[zig]);
      }
      else
      {
         int rs = stbi__jpeg_huff_decode(j, hac);
         if (rs < 0)
            return stbi__err("bad huffman code", "Corrupt JPEG");
         s = rs & 15;
         r = rs >> 4;
         if (s == 0)
         {
            if (rs != 0xf0)
               break; // end block
            k += 16;
         }
         else
         {
            k += r;
            // decode into unzigzag'd location
            zig = stbi__jpeg_dezigzag[k++];
            data[zig] = (short)(stbi__extend_receive(j, s) * dequant[zig]);
         }
      }
   } while (k < 64);
   return 1;
}

static int stbi__jpeg_decode_block_prog_dc(stbi__jpeg *j, short data[64], stbi__huffman *hdc, int b)
{
   int diff, dc;
   int t;
   if (j->spec_end != 0)
      return stbi__err("can't merge dc and ac", "Corrupt JPEG");

   if (j->code_bits < 16)
      stbi__grow_buffer_unsafe(j);

   if (j->succ_high == 0)
   {
      // first scan for DC coefficient, must be first
      memset(data, 0, 64 * sizeof(data[0])); // 0 all the ac values now
      t = stbi__jpeg_huff_decode(j, hdc);
      diff = t ? stbi__extend_receive(j, t) : 0;

      dc = j->img_comp[b].dc_pred + diff;
      j->img_comp[b].dc_pred = dc;
      data[0] = (short)(dc << j->succ_low);
   }
   else
   {
      // refinement scan for DC coefficient
      if (stbi__jpeg_get_bit(j))
         data[0] += (short)(1 << j->succ_low);
   }
   return 1;
}

// @OPTIMIZE: store non-zigzagged during the decode passes,
// and only de-zigzag when dequantizing
static int stbi__jpeg_decode_block_prog_ac(stbi__jpeg *j, short data[64], stbi__huffman *hac, stbi__int16 *fac)
{
   int k;
   if (j->spec_start == 0)
      return stbi__err("can't merge dc and ac", "Corrupt JPEG");

   if (j->succ_high == 0)
   {
      int shift = j->succ_low;

      if (j->eob_run)
      {
         --j->eob_run;
         return 1;
      }

      k = j->spec_start;
      do
      {
         unsigned int zig;
         int c, r, s;
         if (j->code_bits < 16)
            stbi__grow_buffer_unsafe(j);
         c = (j->code_buffer >> (32 - FAST_BITS)) & ((1 << FAST_BITS) - 1);
         r = fac[c];
         if (r)
         {                      // fast-AC path
            k += (r >> 4) & 15; // run
            s = r & 15;         // combined length
            j->code_buffer <<= s;
            j->code_bits -= s;
            zig = stbi__jpeg_dezigzag[k++];
            data[zig] = (short)((r >> 8) << shift);
         }
         else
         {
            int rs = stbi__jpeg_huff_decode(j, hac);
            if (rs < 0)
               return stbi__err("bad huffman code", "Corrupt JPEG");
            s = rs & 15;
            r = rs >> 4;
            if (s == 0)
            {
               if (r < 15)
               {
                  j->eob_run = (1 << r);
                  if (r)
                     j->eob_run += stbi__jpeg_get_bits(j, r);
                  --j->eob_run;
                  break;
               }
               k += 16;
            }
            else
            {
               k += r;
               zig = stbi__jpeg_dezigzag[k++];
               data[zig] = (short)(stbi__extend_receive(j, s) << shift);
            }
         }
      } while (k <= j->spec_end);
   }
   else
   {
      // refinement scan for these AC coefficients

      short bit = (short)(1 << j->succ_low);

      if (j->eob_run)
      {
         --j->eob_run;
         for (k = j->spec_start; k <= j->spec_end; ++k)
         {
            short *p = &data[stbi__jpeg_dezigzag[k]];
            if (*p != 0)
               if (stbi__jpeg_get_bit(j))
                  if ((*p & bit) == 0)
                  {
                     if (*p > 0)
                        *p += bit;
                     else
                        *p -= bit;
                  }
         }
      }
      else
      {
         k = j->spec_start;
         do
         {
            int r, s;
            int rs = stbi__jpeg_huff_decode(j, hac); // @OPTIMIZE see if we can use the fast path here, advance-by-r is so slow, eh
            if (rs < 0)
               return stbi__err("bad huffman code", "Corrupt JPEG");
            s = rs & 15;
            r = rs >> 4;
            if (s == 0)
            {
               if (r < 15)
               {
                  j->eob_run = (1 << r) - 1;
                  if (r)
                     j->eob_run += stbi__jpeg_get_bits(j, r);
                  r = 64; // force end of block
               }
               else
               {
                  // r=15 s=0 should write 16 0s, so we just do
                  // a run of 15 0s and then write s (which is 0),
                  // so we don't have to do anything special here
               }
            }
            else
            {
               if (s != 1)
                  return stbi__err("bad huffman code", "Corrupt JPEG");
               // sign bit
               if (stbi__jpeg_get_bit(j))
                  s = bit;
               else
                  s = -bit;
            }

            // advance by r
            while (k <= j->spec_end)
            {
               short *p = &data[stbi__jpeg_dezigzag[k++]];
               if (*p != 0)
               {
                  if (stbi__jpeg_get_bit(j))
                     if ((*p & bit) == 0)
                     {
                        if (*p > 0)
                           *p += bit;
                        else
                           *p -= bit;
                     }
               }
               else
               {
                  if (r == 0)
                  {
                     *p = (short)s;
                     break;
                  }
                  --r;
               }
            }
         } while (k <= j->spec_end);
      }
   }
   return 1;
}

// take a -128..127 value and stbi__clamp it and convert to 0..255
stbi_inline static stbi_uc stbi__clamp(int x)
{
   // trick to use a single test to catch both cases
   if ((unsigned int)x > 255)
   {
      if (x < 0)
         return 0;
      if (x > 255)
         return 255;
   }
   return (stbi_uc)x;
}

#define stbi__f2f(x) ((int)(((x)*4096 + 0.5)))
#define stbi__fsh(x) ((x)*4096)

// derived from jidctint -- DCT_ISLOW
#define STBI__IDCT_1D(s0, s1, s2, s3, s4, s5, s6, s7)      \
   int t0, t1, t2, t3, p1, p2, p3, p4, p5, x0, x1, x2, x3; \
   p2 = s2;                                                \
   p3 = s6;                                                \
   p1 = (p2 + p3) * stbi__f2f(0.5411961f);                 \
   t2 = p1 + p3 * stbi__f2f(-1.847759065f);                \
   t3 = p1 + p2 * stbi__f2f(0.765366865f);                 \
   p2 = s0;                                                \
   p3 = s4;                                                \
   t0 = stbi__fsh(p2 + p3);                                \
   t1 = stbi__fsh(p2 - p3);                                \
   x0 = t0 + t3;                                           \
   x3 = t0 - t3;                                           \
   x1 = t1 + t2;                                           \
   x2 = t1 - t2;                                           \
   t0 = s7;                                                \
   t1 = s5;                                                \
   t2 = s3;                                                \
   t3 = s1;                                                \
   p3 = t0 + t2;                                           \
   p4 = t1 + t3;                                           \
   p1 = t0 + t3;                                           \
   p2 = t1 + t2;                                           \
   p5 = (p3 + p4) * stbi__f2f(1.175875602f);               \
   t0 = t0 * stbi__f2f(0.298631336f);                      \
   t1 = t1 * stbi__f2f(2.053119869f);                      \
   t2 = t2 * stbi__f2f(3.072711026f);                      \
   t3 = t3 * stbi__f2f(1.501321110f);                      \
   p1 = p5 + p1 * stbi__f2f(-0.899976223f);                \
   p2 = p5 + p2 * stbi__f2f(-2.562915447f);                \
   p3 = p3 * stbi__f2f(-1.961570560f);                     \
   p4 = p4 * stbi__f2f(-0.390180644f);                     \
   t3 += p1 + p4;                                          \
   t2 += p2 + p3;                                          \
   t1 += p2 + p4;                                          \
   t0 += p1 + p3;

static void stbi__idct_block(stbi_uc *out, int out_stride, short data[64])
{
   int i, val[64], *v = val;
   stbi_uc *o;
   short *d = data;

   // columns
   for (i = 0; i < 8; ++i, ++d, ++v)
   {
      // if all zeroes, shortcut -- this avoids dequantizing 0s and IDCTing
      if (d[8] == 0 && d[16] == 0 && d[24] == 0 && d[32] == 0 && d[40] == 0 && d[48] == 0 && d[56] == 0)
      {
         //    no shortcut                 0     seconds
         //    (1|2|3|4|5|6|7)==0          0     seconds
         //    all separate               -0.047 seconds
         //    1 && 2|3 && 4|5 && 6|7:    -0.047 seconds
         int dcterm = d[0] * 4;
         v[0] = v[8] = v[16] = v[24] = v[32] = v[40] = v[48] = v[56] = dcterm;
      }
      else
      {
         STBI__IDCT_1D(d[0], d[8], d[16], d[24], d[32], d[40], d[48], d[56])
         // constants scaled things up by 1<<12; let's bring them back
         // down, but keep 2 extra bits of precision
         x0 += 512;
         x1 += 512;
         x2 += 512;
         x3 += 512;
         v[0] = (x0 + t3) >> 10;
         v[56] = (x0 - t3) >> 10;
         v[8] = (x1 + t2) >> 10;
         v[48] = (x1 - t2) >> 10;
         v[16] = (x2 + t1) >> 10;
         v[40] = (x2 - t1) >> 10;
         v[24] = (x3 + t0) >> 10;
         v[32] = (x3 - t0) >> 10;
      }
   }

   for (i = 0, v = val, o = out; i < 8; ++i, v += 8, o += out_stride)
   {
      // no fast case since the first 1D IDCT spread components out
      STBI__IDCT_1D(v[0], v[1], v[2], v[3], v[4], v[5], v[6], v[7])
      // constants scaled things up by 1<<12, plus we had 1<<2 from first
      // loop, plus horizontal and vertical each scale by sqrt(8) so together
      // we've got an extra 1<<3, so 1<<17 total we need to remove.
      // so we want to round that, which means adding 0.5 * 1<<17,
      // aka 65536. Also, we'll end up with -128 to 127 that we want
      // to encode as 0..255 by adding 128, so we'll add that before the shift
      x0 += 65536 + (128 << 17);
      x1 += 65536 + (128 << 17);
      x2 += 65536 + (128 << 17);
      x3 += 65536 + (128 << 17);
      // tried computing the shifts into temps, or'ing the temps to see
      // if any were out of range, but that was slower
      o[0] = stbi__clamp((x0 + t3) >> 17);
      o[7] = stbi__clamp((x0 - t3) >> 17);
      o[1] = stbi__clamp((x1 + t2) >> 17);
      o[6] = stbi__clamp((x1 - t2) >> 17);
      o[2] = stbi__clamp((x2 + t1) >> 17);
      o[5] = stbi__clamp((x2 - t1) >> 17);
      o[3] = stbi__clamp((x3 + t0) >> 17);
      o[4] = stbi__clamp((x3 - t0) >> 17);
   }
}

#ifdef STBI_SSE2
// sse2 integer IDCT. not the fastest possible implementation but it
// produces bit-identical results to the generic C version so it's
// fully "transparent".
static void stbi__idct_simd(stbi_uc *out, int out_stride, short data[64])
{
   // This is constructed to match our regular (generic) integer IDCT exactly.
   __m128i row0, row1, row2, row3, row4, row5, row6, row7;
   __m128i tmp;

// dot product constant: even elems=x, odd elems=y
#define dct_const(x, y) _mm_setr_epi16((x), (y), (x), (y), (x), (y), (x), (y))

// out(0) = c0[even]*x + c0[odd]*y   (c0, x, y 16-bit, out 32-bit)
// out(1) = c1[even]*x + c1[odd]*y
#define dct_rot(out0, out1, x, y, c0, c1)         \
   __m128i c0##lo = _mm_unpacklo_epi16((x), (y)); \
   __m128i c0##hi = _mm_unpackhi_epi16((x), (y)); \
   __m128i out0##_l = _mm_madd_epi16(c0##lo, c0); \
   __m128i out0##_h = _mm_madd_epi16(c0##hi, c0); \
   __m128i out1##_l = _mm_madd_epi16(c0##lo, c1); \
   __m128i out1##_h = _mm_madd_epi16(c0##hi, c1)

// out = in << 12  (in 16-bit, out 32-bit)
#define dct_widen(out, in)                                                             \
   __m128i out##_l = _mm_srai_epi32(_mm_unpacklo_epi16(_mm_setzero_si128(), (in)), 4); \
   __m128i out##_h = _mm_srai_epi32(_mm_unpackhi_epi16(_mm_setzero_si128(), (in)), 4)

// wide add
#define dct_wadd(out, a, b)                       \
   __m128i out##_l = _mm_add_epi32(a##_l, b##_l); \
   __m128i out##_h = _mm_add_epi32(a##_h, b##_h)

// wide sub
#define dct_wsub(out, a, b)                       \
   __m128i out##_l = _mm_sub_epi32(a##_l, b##_l); \
   __m128i out##_h = _mm_sub_epi32(a##_h, b##_h)

// butterfly a/b, add bias, then shift by "s" and pack
#define dct_bfly32o(out0, out1, a, b, bias, s)                                    \
   {                                                                              \
      __m128i abiased_l = _mm_add_epi32(a##_l, bias);                             \
      __m128i abiased_h = _mm_add_epi32(a##_h, bias);                             \
      dct_wadd(sum, abiased, b);                                                  \
      dct_wsub(dif, abiased, b);                                                  \
      out0 = _mm_packs_epi32(_mm_srai_epi32(sum_l, s), _mm_srai_epi32(sum_h, s)); \
      out1 = _mm_packs_epi32(_mm_srai_epi32(dif_l, s), _mm_srai_epi32(dif_h, s)); \
   }

// 8-bit interleave step (for transposes)
#define dct_interleave8(a, b)   \
   tmp = a;                     \
   a = _mm_unpacklo_epi8(a, b); \
   b = _mm_unpackhi_epi8(tmp, b)

// 16-bit interleave step (for transposes)
#define dct_interleave16(a, b)   \
   tmp = a;                      \
   a = _mm_unpacklo_epi16(a, b); \
   b = _mm_unpackhi_epi16(tmp, b)

#define dct_pass(bias, shift)                          \
   {                                                   \
      /* even part */                                  \
      dct_rot(t2e, t3e, row2, row6, rot0_0, rot0_1);   \
      __m128i sum04 = _mm_add_epi16(row0, row4);       \
      __m128i dif04 = _mm_sub_epi16(row0, row4);       \
      dct_widen(t0e, sum04);                           \
      dct_widen(t1e, dif04);                           \
      dct_wadd(x0, t0e, t3e);                          \
      dct_wsub(x3, t0e, t3e);                          \
      dct_wadd(x1, t1e, t2e);                          \
      dct_wsub(x2, t1e, t2e);                          \
      /* odd part */                                   \
      dct_rot(y0o, y2o, row7, row3, rot2_0, rot2_1);   \
      dct_rot(y1o, y3o, row5, row1, rot3_0, rot3_1);   \
      __m128i sum17 = _mm_add_epi16(row1, row7);       \
      __m128i sum35 = _mm_add_epi16(row3, row5);       \
      dct_rot(y4o, y5o, sum17, sum35, rot1_0, rot1_1); \
      dct_wadd(x4, y0o, y4o);                          \
      dct_wadd(x5, y1o, y5o);                          \
      dct_wadd(x6, y2o, y5o);                          \
      dct_wadd(x7, y3o, y4o);                          \
      dct_bfly32o(row0, row7, x0, x7, bias, shift);    \
      dct_bfly32o(row1, row6, x1, x6, bias, shift);    \
      dct_bfly32o(row2, row5, x2, x5, bias, shift);    \
      dct_bfly32o(row3, row4, x3, x4, bias, shift);    \
   }

   __m128i rot0_0 = dct_const(stbi__f2f(0.5411961f), stbi__f2f(0.5411961f) + stbi__f2f(-1.847759065f));
   __m128i rot0_1 = dct_const(stbi__f2f(0.5411961f) + stbi__f2f(0.765366865f), stbi__f2f(0.5411961f));
   __m128i rot1_0 = dct_const(stbi__f2f(1.175875602f) + stbi__f2f(-0.899976223f), stbi__f2f(1.175875602f));
   __m128i rot1_1 = dct_const(stbi__f2f(1.175875602f), stbi__f2f(1.175875602f) + stbi__f2f(-2.562915447f));
   __m128i rot2_0 = dct_const(stbi__f2f(-1.961570560f) + stbi__f2f(0.298631336f), stbi__f2f(-1.961570560f));
   __m128i rot2_1 = dct_const(stbi__f2f(-1.961570560f), stbi__f2f(-1.961570560f) + stbi__f2f(3.072711026f));
   __m128i rot3_0 = dct_const(stbi__f2f(-0.390180644f) + stbi__f2f(2.053119869f), stbi__f2f(-0.390180644f));
   __m128i rot3_1 = dct_const(stbi__f2f(-0.390180644f), stbi__f2f(-0.390180644f) + stbi__f2f(1.501321110f));

   // rounding biases in column/row passes, see stbi__idct_block for explanation.
   __m128i bias_0 = _mm_set1_epi32(512);
   __m128i bias_1 = _mm_set1_epi32(65536 + (128 << 17));

   // load
   row0 = _mm_load_si128((const __m128i *)(data + 0 * 8));
   row1 = _mm_load_si128((const __m128i *)(data + 1 * 8));
   row2 = _mm_load_si128((const __m128i *)(data + 2 * 8));
   row3 = _mm_load_si128((const __m128i *)(data + 3 * 8));
   row4 = _mm_load_si128((const __m128i *)(data + 4 * 8));
   row5 = _mm_load_si128((const __m128i *)(data + 5 * 8));
   row6 = _mm_load_si128((const __m128i *)(data + 6 * 8));
   row7 = _mm_load_si128((const __m128i *)(data + 7 * 8));

   // column pass
   dct_pass(bias_0, 10);

   {
      // 16bit 8x8 transpose pass 1
      dct_interleave16(row0, row4);
      dct_interleave16(row1, row5);
      dct_interleave16(row2, row6);
      dct_interleave16(row3, row7);

      // transpose pass 2
      dct_interleave16(row0, row2);
      dct_interleave16(row1, row3);
      dct_interleave16(row4, row6);
      dct_interleave16(row5, row7);

      // transpose pass 3
      dct_interleave16(row0, row1);
      dct_interleave16(row2, row3);
      dct_interleave16(row4, row5);
      dct_interleave16(row6, row7);
   }

   // row pass
   dct_pass(bias_1, 17);

   {
      // pack
      __m128i p0 = _mm_packus_epi16(row0, row1); // a0a1a2a3...a7b0b1b2b3...b7
      __m128i p1 = _mm_packus_epi16(row2, row3);
      __m128i p2 = _mm_packus_epi16(row4, row5);
      __m128i p3 = _mm_packus_epi16(row6, row7);

      // 8bit 8x8 transpose pass 1
      dct_interleave8(p0, p2); // a0e0a1e1...
      dct_interleave8(p1, p3); // c0g0c1g1...

      // transpose pass 2
      dct_interleave8(p0, p1); // a0c0e0g0...
      dct_interleave8(p2, p3); // b0d0f0h0...

      // transpose pass 3
      dct_interleave8(p0, p2); // a0b0c0d0...
      dct_interleave8(p1, p3); // a4b4c4d4...

      // store
      _mm_storel_epi64((__m128i *)out, p0);
      out += out_stride;
      _mm_storel_epi64((__m128i *)out, _mm_shuffle_epi32(p0, 0x4e));
      out += out_stride;
      _mm_storel_epi64((__m128i *)out, p2);
      out += out_stride;
      _mm_storel_epi64((__m128i *)out, _mm_shuffle_epi32(p2, 0x4e));
      out += out_stride;
      _mm_storel_epi64((__m128i *)out, p1);
      out += out_stride;
      _mm_storel_epi64((__m128i *)out, _mm_shuffle_epi32(p1, 0x4e));
      out += out_stride;
      _mm_storel_epi64((__m128i *)out, p3);
      out += out_stride;
      _mm_storel_epi64((__m128i *)out, _mm_shuffle_epi32(p3, 0x4e));
   }

#undef dct_const
#undef dct_rot
#undef dct_widen
#undef dct_wadd
#undef dct_wsub
#undef dct_bfly32o
#undef dct_interleave8
#undef dct_interleave16
#undef dct_pass
}

#endif // STBI_SSE2

#ifdef STBI_NEON

// NEON integer IDCT. should produce bit-identical
// results to the generic C version.
static void stbi__idct_simd(stbi_uc *out, int out_stride, short data[64])
{
   int16x8_t row0, row1, row2, row3, row4, row5, row6, row7;

   int16x4_t rot0_0 = vdup_n_s16(stbi__f2f(0.5411961f));
   int16x4_t rot0_1 = vdup_n_s16(stbi__f2f(-1.847759065f));
   int16x4_t rot0_2 = vdup_n_s16(stbi__f2f(0.765366865f));
   int16x4_t rot1_0 = vdup_n_s16(stbi__f2f(1.175875602f));
   int16x4_t rot1_1 = vdup_n_s16(stbi__f2f(-0.899976223f));
   int16x4_t rot1_2 = vdup_n_s16(stbi__f2f(-2.562915447f));
   int16x4_t rot2_0 = vdup_n_s16(stbi__f2f(-1.961570560f));
   int16x4_t rot2_1 = vdup_n_s16(stbi__f2f(-0.390180644f));
   int16x4_t rot3_0 = vdup_n_s16(stbi__f2f(0.298631336f));
   int16x4_t rot3_1 = vdup_n_s16(stbi__f2f(2.053119869f));
   int16x4_t rot3_2 = vdup_n_s16(stbi__f2f(3.072711026f));
   int16x4_t rot3_3 = vdup_n_s16(stbi__f2f(1.501321110f));

#define dct_long_mul(out, inq, coeff)                       \
   int32x4_t out##_l = vmull_s16(vget_low_s16(inq), coeff); \
   int32x4_t out##_h = vmull_s16(vget_high_s16(inq), coeff)

#define dct_long_mac(out, acc, inq, coeff)                           \
   int32x4_t out##_l = vmlal_s16(acc##_l, vget_low_s16(inq), coeff); \
   int32x4_t out##_h = vmlal_s16(acc##_h, vget_high_s16(inq), coeff)

#define dct_widen(out, inq)                                \
   int32x4_t out##_l = vshll_n_s16(vget_low_s16(inq), 12); \
   int32x4_t out##_h = vshll_n_s16(vget_high_s16(inq), 12)

// wide add
#define dct_wadd(out, a, b)                     \
   int32x4_t out##_l = vaddq_s32(a##_l, b##_l); \
   int32x4_t out##_h = vaddq_s32(a##_h, b##_h)

// wide sub
#define dct_wsub(out, a, b)                     \
   int32x4_t out##_l = vsubq_s32(a##_l, b##_l); \
   int32x4_t out##_h = vsubq_s32(a##_h, b##_h)

// butterfly a/b, then shift using "shiftop" by "s" and pack
#define dct_bfly32o(out0, out1, a, b, shiftop, s)                \
   {                                                             \
      dct_wadd(sum, a, b);                                       \
      dct_wsub(dif, a, b);                                       \
      out0 = vcombine_s16(shiftop(sum_l, s), shiftop(sum_h, s)); \
      out1 = vcombine_s16(shiftop(dif_l, s), shiftop(dif_h, s)); \
   }

#define dct_pass(shiftop, shift)                       \
   {                                                   \
      /* even part */                                  \
      int16x8_t sum26 = vaddq_s16(row2, row6);         \
      dct_long_mul(p1e, sum26, rot0_0);                \
      dct_long_mac(t2e, p1e, row6, rot0_1);            \
      dct_long_mac(t3e, p1e, row2, rot0_2);            \
      int16x8_t sum04 = vaddq_s16(row0, row4);         \
      int16x8_t dif04 = vsubq_s16(row0, row4);         \
      dct_widen(t0e, sum04);                           \
      dct_widen(t1e, dif04);                           \
      dct_wadd(x0, t0e, t3e);                          \
      dct_wsub(x3, t0e, t3e);                          \
      dct_wadd(x1, t1e, t2e);                          \
      dct_wsub(x2, t1e, t2e);                          \
      /* odd part */                                   \
      int16x8_t sum15 = vaddq_s16(row1, row5);         \
      int16x8_t sum17 = vaddq_s16(row1, row7);         \
      int16x8_t sum35 = vaddq_s16(row3, row5);         \
      int16x8_t sum37 = vaddq_s16(row3, row7);         \
      int16x8_t sumodd = vaddq_s16(sum17, sum35);      \
      dct_long_mul(p5o, sumodd, rot1_0);               \
      dct_long_mac(p1o, p5o, sum17, rot1_1);           \
      dct_long_mac(p2o, p5o, sum35, rot1_2);           \
      dct_long_mul(p3o, sum37, rot2_0);                \
      dct_long_mul(p4o, sum15, rot2_1);                \
      dct_wadd(sump13o, p1o, p3o);                     \
      dct_wadd(sump24o, p2o, p4o);                     \
      dct_wadd(sump23o, p2o, p3o);                     \
      dct_wadd(sump14o, p1o, p4o);                     \
      dct_long_mac(x4, sump13o, row7, rot3_0);         \
      dct_long_mac(x5, sump24o, row5, rot3_1);         \
      dct_long_mac(x6, sump23o, row3, rot3_2);         \
      dct_long_mac(x7, sump14o, row1, rot3_3);         \
      dct_bfly32o(row0, row7, x0, x7, shiftop, shift); \
      dct_bfly32o(row1, row6, x1, x6, shiftop, shift); \
      dct_bfly32o(row2, row5, x2, x5, shiftop, shift); \
      dct_bfly32o(row3, row4, x3, x4, shiftop, shift); \
   }

   // load
   row0 = vld1q_s16(data + 0 * 8);
   row1 = vld1q_s16(data + 1 * 8);
   row2 = vld1q_s16(data + 2 * 8);
   row3 = vld1q_s16(data + 3 * 8);
   row4 = vld1q_s16(data + 4 * 8);
   row5 = vld1q_s16(data + 5 * 8);
   row6 = vld1q_s16(data + 6 * 8);
   row7 = vld1q_s16(data + 7 * 8);

   // add DC bias
   row0 = vaddq_s16(row0, vsetq_lane_s16(1024, vdupq_n_s16(0), 0));

   // column pass
   dct_pass(vrshrn_n_s32, 10);

   // 16bit 8x8 transpose
   {
// these three map to a single VTRN.16, VTRN.32, and VSWP, respectively.
// whether compilers actually get this is another story, sadly.
#define dct_trn16(x, y)                \
   {                                   \
      int16x8x2_t t = vtrnq_s16(x, y); \
      x = t.val[0];                    \
      y = t.val[1];                    \
   }
#define dct_trn32(x, y)                                                              \
   {                                                                                 \
      int32x4x2_t t = vtrnq_s32(vreinterpretq_s32_s16(x), vreinterpretq_s32_s16(y)); \
      x = vreinterpretq_s16_s32(t.val[0]);                                           \
      y = vreinterpretq_s16_s32(t.val[1]);                                           \
   }
#define dct_trn64(x, y)                                       \
   {                                                          \
      int16x8_t x0 = x;                                       \
      int16x8_t y0 = y;                                       \
      x = vcombine_s16(vget_low_s16(x0), vget_low_s16(y0));   \
      y = vcombine_s16(vget_high_s16(x0), vget_high_s16(y0)); \
   }

      // pass 1
      dct_trn16(row0, row1); // a0b0a2b2a4b4a6b6
      dct_trn16(row2, row3);
      dct_trn16(row4, row5);
      dct_trn16(row6, row7);

      // pass 2
      dct_trn32(row0, row2); // a0b0c0d0a4b4c4d4
      dct_trn32(row1, row3);
      dct_trn32(row4, row6);
      dct_trn32(row5, row7);

      // pass 3
      dct_trn64(row0, row4); // a0b0c0d0e0f0g0h0
      dct_trn64(row1, row5);
      dct_trn64(row2, row6);
      dct_trn64(row3, row7);

#undef dct_trn16
#undef dct_trn32
#undef dct_trn64
   }

   // row pass
   // vrshrn_n_s32 only supports shifts up to 16, we need
   // 17. so do a non-rounding shift of 16 first then follow
   // up with a rounding shift by 1.
   dct_pass(vshrn_n_s32, 16);

   {
      // pack and round
      uint8x8_t p0 = vqrshrun_n_s16(row0, 1);
      uint8x8_t p1 = vqrshrun_n_s16(row1, 1);
      uint8x8_t p2 = vqrshrun_n_s16(row2, 1);
      uint8x8_t p3 = vqrshrun_n_s16(row3, 1);
      uint8x8_t p4 = vqrshrun_n_s16(row4, 1);
      uint8x8_t p5 = vqrshrun_n_s16(row5, 1);
      uint8x8_t p6 = vqrshrun_n_s16(row6, 1);
      uint8x8_t p7 = vqrshrun_n_s16(row7, 1);

      // again, these can translate into one instruction, but often don't.
#define dct_trn8_8(x, y)             \
   {                                 \
      uint8x8x2_t t = vtrn_u8(x, y); \
      x = t.val[0];                  \
      y = t.val[1];                  \
   }
#define dct_trn8_16(x, y)                                                        \
   {                                                                             \
      uint16x4x2_t t = vtrn_u16(vreinterpret_u16_u8(x), vreinterpret_u16_u8(y)); \
      x = vreinterpret_u8_u16(t.val[0]);                                         \
      y = vreinterpret_u8_u16(t.val[1]);                                         \
   }
#define dct_trn8_32(x, y)                                                        \
   {                                                                             \
      uint32x2x2_t t = vtrn_u32(vreinterpret_u32_u8(x), vreinterpret_u32_u8(y)); \
      x = vreinterpret_u8_u32(t.val[0]);                                         \
      y = vreinterpret_u8_u32(t.val[1]);                                         \
   }

      // sadly can't use interleaved stores here since we only write
      // 8 bytes to each scan line!

      // 8x8 8-bit transpose pass 1
      dct_trn8_8(p0, p1);
      dct_trn8_8(p2, p3);
      dct_trn8_8(p4, p5);
      dct_trn8_8(p6, p7);

      // pass 2
      dct_trn8_16(p0, p2);
      dct_trn8_16(p1, p3);
      dct_trn8_16(p4, p6);
      dct_trn8_16(p5, p7);

      // pass 3
      dct_trn8_32(p0, p4);
      dct_trn8_32(p1, p5);
      dct_trn8_32(p2, p6);
      dct_trn8_32(p3, p7);

      // store
      vst1_u8(out, p0);
      out += out_stride;
      vst1_u8(out, p1);
      out += out_stride;
      vst1_u8(out, p2);
      out += out_stride;
      vst1_u8(out, p3);
      out += out_stride;
      vst1_u8(out, p4);
      out += out_stride;
      vst1_u8(out, p5);
      out += out_stride;
      vst1_u8(out, p6);
      out += out_stride;
      vst1_u8(out, p7);

#undef dct_trn8_8
#undef dct_trn8_16
#undef dct_trn8_32
   }

#undef dct_long_mul
#undef dct_long_mac
#undef dct_widen
#undef dct_wadd
#undef dct_wsub
#undef dct_bfly32o
#undef dct_pass
}

#endif // STBI_NEON

#define STBI__MARKER_none 0xff
// if there's a pending marker from the entropy stream, return that
// otherwise, fetch from the stream and get a marker. if there's no
// marker, return 0xff, which is never a valid marker value
static stbi_uc stbi__get_marker(stbi__jpeg *j)
{
   stbi_uc x;
   if (j->marker != STBI__MARKER_none)
   {
      x = j->marker;
      j->marker = STBI__MARKER_none;
      return x;
   }
   x = stbi__get8(j->s);
   if (x != 0xff)
      return STBI__MARKER_none;
   while (x == 0xff)
      x = stbi__get8(j->s); // consume repeated 0xff fill bytes
   return x;
}

// in each scan, we'll have scan_n components, and the order
// of the components is specified by order[]
#define STBI__RESTART(x) ((x) >= 0xd0 && (x) <= 0xd7)

// after a restart interval, stbi__jpeg_reset the entropy decoder and
// the dc prediction
static void stbi__jpeg_reset(stbi__jpeg *j)
{
   j->code_bits = 0;
   j->code_buffer = 0;
   j->nomore = 0;
   j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = j->img_comp[3].dc_pred = 0;
   j->marker = STBI__MARKER_none;
   j->todo = j->restart_interval ? j->restart_interval : 0x7fffffff;
   j->eob_run = 0;
   // no more than 1<<31 MCUs if no restart_interal? that's plenty safe,
   // since we don't even allow 1<<30 pixels
}

static int stbi__parse_entropy_coded_data(stbi__jpeg *z)
{
   stbi__jpeg_reset(z);
   if (!z->progressive)
   {
      if (z->scan_n == 1)
      {
         int i, j;
         STBI_SIMD_ALIGN(short, data[64]);
         int n = z->order[0];
         // non-interleaved data, we just need to process one block at a time,
         // in trivial scanline order
         // number of blocks to do just depends on how many actual "pixels" this
         // component has, independent of interleaved MCU blocking and such
         int w = (z->img_comp[n].x + 7) >> 3;
         int h = (z->img_comp[n].y + 7) >> 3;
         for (j = 0; j < h; ++j)
         {
            for (i = 0; i < w; ++i)
            {
               int ha = z->img_comp[n].ha;
               if (!stbi__jpeg_decode_block(z, data, z->huff_dc + z->img_comp[n].hd, z->huff_ac + ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq]))
                  return 0;
               z->idct_block_kernel(z->img_comp[n].data + z->img_comp[n].w2 * j * 8 + i * 8, z->img_comp[n].w2, data);
               // every data block is an MCU, so countdown the restart interval
               if (--z->todo <= 0)
               {
                  if (z->code_bits < 24)
                     stbi__grow_buffer_unsafe(z);
                  // if it's NOT a restart, then just bail, so we get corrupt data
                  // rather than no data
                  if (!STBI__RESTART(z->marker))
                     return 1;
                  stbi__jpeg_reset(z);
               }
            }
         }
         return 1;
      }
      else
      { // interleaved
         int i, j, k, x, y;
         STBI_SIMD_ALIGN(short, data[64]);
         for (j = 0; j < z->img_mcu_y; ++j)
         {
            for (i = 0; i < z->img_mcu_x; ++i)
            {
               // scan an interleaved mcu... process scan_n components in order
               for (k = 0; k < z->scan_n; ++k)
               {
                  int n = z->order[k];
                  // scan out an mcu's worth of this component; that's just determined
                  // by the basic H and V specified for the component
                  for (y = 0; y < z->img_comp[n].v; ++y)
                  {
                     for (x = 0; x < z->img_comp[n].h; ++x)
                     {
                        int x2 = (i * z->img_comp[n].h + x) * 8;
                        int y2 = (j * z->img_comp[n].v + y) * 8;
                        int ha = z->img_comp[n].ha;
                        if (!stbi__jpeg_decode_block(z, data, z->huff_dc + z->img_comp[n].hd, z->huff_ac + ha, z->fast_ac[ha], n, z->dequant[z->img_comp[n].tq]))
                           return 0;
                        z->idct_block_kernel(z->img_comp[n].data + z->img_comp[n].w2 * y2 + x2, z->img_comp[n].w2, data);
                     }
                  }
               }
               // after all interleaved components, that's an interleaved MCU,
               // so now count down the restart interval
               if (--z->todo <= 0)
               {
                  if (z->code_bits < 24)
                     stbi__grow_buffer_unsafe(z);
                  if (!STBI__RESTART(z->marker))
                     return 1;
                  stbi__jpeg_reset(z);
               }
            }
         }
         return 1;
      }
   }
   else
   {
      if (z->scan_n == 1)
      {
         int i, j;
         int n = z->order[0];
         // non-interleaved data, we just need to process one block at a time,
         // in trivial scanline order
         // number of blocks to do just depends on how many actual "pixels" this
         // component has, independent of interleaved MCU blocking and such
         int w = (z->img_comp[n].x + 7) >> 3;
         int h = (z->img_comp[n].y + 7) >> 3;
         for (j = 0; j < h; ++j)
         {
            for (i = 0; i < w; ++i)
            {
               short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w);
               if (z->spec_start == 0)
               {
                  if (!stbi__jpeg_decode_block_prog_dc(z, data, &z->huff_dc[z->img_comp[n].hd], n))
                     return 0;
               }
               else
               {
                  int ha = z->img_comp[n].ha;
                  if (!stbi__jpeg_decode_block_prog_ac(z, data, &z->huff_ac[ha], z->fast_ac[ha]))
                     return 0;
               }
               // every data block is an MCU, so countdown the restart interval
               if (--z->todo <= 0)
               {
                  if (z->code_bits < 24)
                     stbi__grow_buffer_unsafe(z);
                  if (!STBI__RESTART(z->marker))
                     return 1;
                  stbi__jpeg_reset(z);
               }
            }
         }
         return 1;
      }
      else
      { // interleaved
         int i, j, k, x, y;
         for (j = 0; j < z->img_mcu_y; ++j)
         {
            for (i = 0; i < z->img_mcu_x; ++i)
            {
               // scan an interleaved mcu... process scan_n components in order
               for (k = 0; k < z->scan_n; ++k)
               {
                  int n = z->order[k];
                  // scan out an mcu's worth of this component; that's just determined
                  // by the basic H and V specified for the component
                  for (y = 0; y < z->img_comp[n].v; ++y)
                  {
                     for (x = 0; x < z->img_comp[n].h; ++x)
                     {
                        int x2 = (i * z->img_comp[n].h + x);
                        int y2 = (j * z->img_comp[n].v + y);
                        short *data = z->img_comp[n].coeff + 64 * (x2 + y2 * z->img_comp[n].coeff_w);
                        if (!stbi__jpeg_decode_block_prog_dc(z, data, &z->huff_dc[z->img_comp[n].hd], n))
                           return 0;
                     }
                  }
               }
               // after all interleaved components, that's an interleaved MCU,
               // so now count down the restart interval
               if (--z->todo <= 0)
               {
                  if (z->code_bits < 24)
                     stbi__grow_buffer_unsafe(z);
                  if (!STBI__RESTART(z->marker))
                     return 1;
                  stbi__jpeg_reset(z);
               }
            }
         }
         return 1;
      }
   }
}

static void stbi__jpeg_dequantize(short *data, stbi__uint16 *dequant)
{
   int i;
   for (i = 0; i < 64; ++i)
      data[i] *= dequant[i];
}

static void stbi__jpeg_finish(stbi__jpeg *z)
{
   if (z->progressive)
   {
      // dequantize and idct the data
      int i, j, n;
      for (n = 0; n < z->s->img_n; ++n)
      {
         int w = (z->img_comp[n].x + 7) >> 3;
         int h = (z->img_comp[n].y + 7) >> 3;
         for (j = 0; j < h; ++j)
         {
            for (i = 0; i < w; ++i)
            {
               short *data = z->img_comp[n].coeff + 64 * (i + j * z->img_comp[n].coeff_w);
               stbi__jpeg_dequantize(data, z->dequant[z->img_comp[n].tq]);
               z->idct_block_kernel(z->img_comp[n].data + z->img_comp[n].w2 * j * 8 + i * 8, z->img_comp[n].w2, data);
            }
         }
      }
   }
}

static int stbi__process_marker(stbi__jpeg *z, int m)
{
   int L;
   switch (m)
   {
   case STBI__MARKER_none: // no marker found
      return stbi__err("expected marker", "Corrupt JPEG");

   case 0xDD: // DRI - specify restart interval
      if (stbi__get16be(z->s) != 4)
         return stbi__err("bad DRI len", "Corrupt JPEG");
      z->restart_interval = stbi__get16be(z->s);
      return 1;

   case 0xDB: // DQT - define quantization table
      L = stbi__get16be(z->s) - 2;
      while (L > 0)
      {
         int q = stbi__get8(z->s);
         int p = q >> 4, sixteen = (p != 0);
         int t = q & 15, i;
         if (p != 0 && p != 1)
            return stbi__err("bad DQT type", "Corrupt JPEG");
         if (t > 3)
            return stbi__err("bad DQT table", "Corrupt JPEG");

         for (i = 0; i < 64; ++i)
            z->dequant[t][stbi__jpeg_dezigzag[i]] = (stbi__uint16)(sixteen ? stbi__get16be(z->s) : stbi__get8(z->s));
         L -= (sixteen ? 129 : 65);
      }
      return L == 0;

   case 0xC4: // DHT - define huffman table
      L = stbi__get16be(z->s) - 2;
      while (L > 0)
      {
         stbi_uc *v;
         int sizes[16], i, n = 0;
         int q = stbi__get8(z->s);
         int tc = q >> 4;
         int th = q & 15;
         if (tc > 1 || th > 3)
            return stbi__err("bad DHT header", "Corrupt JPEG");
         for (i = 0; i < 16; ++i)
         {
            sizes[i] = stbi__get8(z->s);
            n += sizes[i];
         }
         L -= 17;
         if (tc == 0)
         {
            if (!stbi__build_huffman(z->huff_dc + th, sizes))
               return 0;
            v = z->huff_dc[th].values;
         }
         else
         {
            if (!stbi__build_huffman(z->huff_ac + th, sizes))
               return 0;
            v = z->huff_ac[th].values;
         }
         for (i = 0; i < n; ++i)
            v[i] = stbi__get8(z->s);
         if (tc != 0)
            stbi__build_fast_ac(z->fast_ac[th], z->huff_ac + th);
         L -= n;
      }
      return L == 0;
   }

   // check for comment block or APP blocks
   if ((m >= 0xE0 && m <= 0xEF) || m == 0xFE)
   {
      L = stbi__get16be(z->s);
      if (L < 2)
      {
         if (m == 0xFE)
            return stbi__err("bad COM len", "Corrupt JPEG");
         else
            return stbi__err("bad APP len", "Corrupt JPEG");
      }
      L -= 2;

      if (m == 0xE0 && L >= 5)
      { // JFIF APP0 segment
         static const unsigned char tag[5] = {'J', 'F', 'I', 'F', '\0'};
         int ok = 1;
         int i;
         for (i = 0; i < 5; ++i)
            if (stbi__get8(z->s) != tag[i])
               ok = 0;
         L -= 5;
         if (ok)
            z->jfif = 1;
      }
      else if (m == 0xEE && L >= 12)
      { // Adobe APP14 segment
         static const unsigned char tag[6] = {'A', 'd', 'o', 'b', 'e', '\0'};
         int ok = 1;
         int i;
         for (i = 0; i < 6; ++i)
            if (stbi__get8(z->s) != tag[i])
               ok = 0;
         L -= 6;
         if (ok)
         {
            stbi__get8(z->s);                            // version
            stbi__get16be(z->s);                         // flags0
            stbi__get16be(z->s);                         // flags1
            z->app14_color_transform = stbi__get8(z->s); // color transform
            L -= 6;
         }
      }

      stbi__skip(z->s, L);
      return 1;
   }

   return stbi__err("unknown marker", "Corrupt JPEG");
}

// after we see SOS
static int stbi__process_scan_header(stbi__jpeg *z)
{
   int i;
   int Ls = stbi__get16be(z->s);
   z->scan_n = stbi__get8(z->s);
   if (z->scan_n < 1 || z->scan_n > 4 || z->scan_n > (int)z->s->img_n)
      return stbi__err("bad SOS component count", "Corrupt JPEG");
   if (Ls != 6 + 2 * z->scan_n)
      return stbi__err("bad SOS len", "Corrupt JPEG");
   for (i = 0; i < z->scan_n; ++i)
   {
      int id = stbi__get8(z->s), which;
      int q = stbi__get8(z->s);
      for (which = 0; which < z->s->img_n; ++which)
         if (z->img_comp[which].id == id)
            break;
      if (which == z->s->img_n)
         return 0; // no match
      z->img_comp[which].hd = q >> 4;
      if (z->img_comp[which].hd > 3)
         return stbi__err("bad DC huff", "Corrupt JPEG");
      z->img_comp[which].ha = q & 15;
      if (z->img_comp[which].ha > 3)
         return stbi__err("bad AC huff", "Corrupt JPEG");
      z->order[i] = which;
   }

   {
      int aa;
      z->spec_start = stbi__get8(z->s);
      z->spec_end = stbi__get8(z->s); // should be 63, but might be 0
      aa = stbi__get8(z->s);
      z->succ_high = (aa >> 4);
      z->succ_low = (aa & 15);
      if (z->progressive)
      {
         if (z->spec_start > 63 || z->spec_end > 63 || z->spec_start > z->spec_end || z->succ_high > 13 || z->succ_low > 13)
            return stbi__err("bad SOS", "Corrupt JPEG");
      }
      else
      {
         if (z->spec_start != 0)
            return stbi__err("bad SOS", "Corrupt JPEG");
         if (z->succ_high != 0 || z->succ_low != 0)
            return stbi__err("bad SOS", "Corrupt JPEG");
         z->spec_end = 63;
      }
   }

   return 1;
}

static int stbi__free_jpeg_components(stbi__jpeg *z, int ncomp, int why)
{
   int i;
   for (i = 0; i < ncomp; ++i)
   {
      if (z->img_comp[i].raw_data)
      {
         STBI_FREE(z->img_comp[i].raw_data);
         z->img_comp[i].raw_data = NULL;
         z->img_comp[i].data = NULL;
      }
      if (z->img_comp[i].raw_coeff)
      {
         STBI_FREE(z->img_comp[i].raw_coeff);
         z->img_comp[i].raw_coeff = 0;
         z->img_comp[i].coeff = 0;
      }
      if (z->img_comp[i].linebuf)
      {
         STBI_FREE(z->img_comp[i].linebuf);
         z->img_comp[i].linebuf = NULL;
      }
   }
   return why;
}

static int stbi__process_frame_header(stbi__jpeg *z, int scan)
{
   stbi__context *s = z->s;
   int Lf, p, i, q, h_max = 1, v_max = 1, c;
   Lf = stbi__get16be(s);
   if (Lf < 11)
      return stbi__err("bad SOF len", "Corrupt JPEG"); // JPEG
   p = stbi__get8(s);
   if (p != 8)
      return stbi__err("only 8-bit", "JPEG format not supported: 8-bit only"); // JPEG baseline
   s->img_y = stbi__get16be(s);
   if (s->img_y == 0)
      return stbi__err("no header height", "JPEG format not supported: delayed height"); // Legal, but we don't handle it--but neither does IJG
   s->img_x = stbi__get16be(s);
   if (s->img_x == 0)
      return stbi__err("0 width", "Corrupt JPEG"); // JPEG requires
   c = stbi__get8(s);
   if (c != 3 && c != 1 && c != 4)
      return stbi__err("bad component count", "Corrupt JPEG");
   s->img_n = c;
   for (i = 0; i < c; ++i)
   {
      z->img_comp[i].data = NULL;
      z->img_comp[i].linebuf = NULL;
   }

   if (Lf != 8 + 3 * s->img_n)
      return stbi__err("bad SOF len", "Corrupt JPEG");

   z->rgb = 0;
   for (i = 0; i < s->img_n; ++i)
   {
      static const unsigned char rgb[3] = {'R', 'G', 'B'};
      z->img_comp[i].id = stbi__get8(s);
      if (s->img_n == 3 && z->img_comp[i].id == rgb[i])
         ++z->rgb;
      q = stbi__get8(s);
      z->img_comp[i].h = (q >> 4);
      if (!z->img_comp[i].h || z->img_comp[i].h > 4)
         return stbi__err("bad H", "Corrupt JPEG");
      z->img_comp[i].v = q & 15;
      if (!z->img_comp[i].v || z->img_comp[i].v > 4)
         return stbi__err("bad V", "Corrupt JPEG");
      z->img_comp[i].tq = stbi__get8(s);
      if (z->img_comp[i].tq > 3)
         return stbi__err("bad TQ", "Corrupt JPEG");
   }

   if (scan != STBI__SCAN_load)
      return 1;

   if (!stbi__mad3sizes_valid(s->img_x, s->img_y, s->img_n, 0))
      return stbi__err("too large", "Image too large to decode");

   for (i = 0; i < s->img_n; ++i)
   {
      if (z->img_comp[i].h > h_max)
         h_max = z->img_comp[i].h;
      if (z->img_comp[i].v > v_max)
         v_max = z->img_comp[i].v;
   }

   // compute interleaved mcu info
   z->img_h_max = h_max;
   z->img_v_max = v_max;
   z->img_mcu_w = h_max * 8;
   z->img_mcu_h = v_max * 8;
   // these sizes can't be more than 17 bits
   z->img_mcu_x = (s->img_x + z->img_mcu_w - 1) / z->img_mcu_w;
   z->img_mcu_y = (s->img_y + z->img_mcu_h - 1) / z->img_mcu_h;

   for (i = 0; i < s->img_n; ++i)
   {
      // number of effective pixels (e.g. for non-interleaved MCU)
      z->img_comp[i].x = (s->img_x * z->img_comp[i].h + h_max - 1) / h_max;
      z->img_comp[i].y = (s->img_y * z->img_comp[i].v + v_max - 1) / v_max;
      // to simplify generation, we'll allocate enough memory to decode
      // the bogus oversized data from using interleaved MCUs and their
      // big blocks (e.g. a 16x16 iMCU on an image of width 33); we won't
      // discard the extra data until colorspace conversion
      //
      // img_mcu_x, img_mcu_y: <=17 bits; comp[i].h and .v are <=4 (checked earlier)
      // so these muls can't overflow with 32-bit ints (which we require)
      z->img_comp[i].w2 = z->img_mcu_x * z->img_comp[i].h * 8;
      z->img_comp[i].h2 = z->img_mcu_y * z->img_comp[i].v * 8;
      z->img_comp[i].coeff = 0;
      z->img_comp[i].raw_coeff = 0;
      z->img_comp[i].linebuf = NULL;
      z->img_comp[i].raw_data = stbi__malloc_mad2(z->img_comp[i].w2, z->img_comp[i].h2, 15);
      if (z->img_comp[i].raw_data == NULL)
         return stbi__free_jpeg_components(z, i + 1, stbi__err("outofmem", "Out of memory"));
      // align blocks for idct using mmx/sse
      z->img_comp[i].data = (stbi_uc *)(((size_t)z->img_comp[i].raw_data + 15) & ~15);
      if (z->progressive)
      {
         // w2, h2 are multiples of 8 (see above)
         z->img_comp[i].coeff_w = z->img_comp[i].w2 / 8;
         z->img_comp[i].coeff_h = z->img_comp[i].h2 / 8;
         z->img_comp[i].raw_coeff = stbi__malloc_mad3(z->img_comp[i].w2, z->img_comp[i].h2, sizeof(short), 15);
         if (z->img_comp[i].raw_coeff == NULL)
            return stbi__free_jpeg_components(z, i + 1, stbi__err("outofmem", "Out of memory"));
         z->img_comp[i].coeff = (short *)(((size_t)z->img_comp[i].raw_coeff + 15) & ~15);
      }
   }

   return 1;
}

// use comparisons since in some cases we handle more than one case (e.g. SOF)
#define stbi__DNL(x) ((x) == 0xdc)
#define stbi__SOI(x) ((x) == 0xd8)
#define stbi__EOI(x) ((x) == 0xd9)
#define stbi__SOF(x) ((x) == 0xc0 || (x) == 0xc1 || (x) == 0xc2)
#define stbi__SOS(x) ((x) == 0xda)

#define stbi__SOF_progressive(x) ((x) == 0xc2)

static int stbi__decode_jpeg_header(stbi__jpeg *z, int scan)
{
   int m;
   z->jfif = 0;
   z->app14_color_transform = -1; // valid values are 0,1,2
   z->marker = STBI__MARKER_none; // initialize cached marker to empty
   m = stbi__get_marker(z);
   if (!stbi__SOI(m))
      return stbi__err("no SOI", "Corrupt JPEG");
   if (scan == STBI__SCAN_type)
      return 1;
   m = stbi__get_marker(z);
   while (!stbi__SOF(m))
   {
      if (!stbi__process_marker(z, m))
         return 0;
      m = stbi__get_marker(z);
      while (m == STBI__MARKER_none)
      {
         // some files have extra padding after their blocks, so ok, we'll scan
         if (stbi__at_eof(z->s))
            return stbi__err("no SOF", "Corrupt JPEG");
         m = stbi__get_marker(z);
      }
   }
   z->progressive = stbi__SOF_progressive(m);
   if (!stbi__process_frame_header(z, scan))
      return 0;
   return 1;
}

// decode image to YCbCr format
static int stbi__decode_jpeg_image(stbi__jpeg *j)
{
   int m;
   for (m = 0; m < 4; m++)
   {
      j->img_comp[m].raw_data = NULL;
      j->img_comp[m].raw_coeff = NULL;
   }
   j->restart_interval = 0;
   if (!stbi__decode_jpeg_header(j, STBI__SCAN_load))
      return 0;
   m = stbi__get_marker(j);
   while (!stbi__EOI(m))
   {
      if (stbi__SOS(m))
      {
         if (!stbi__process_scan_header(j))
            return 0;
         if (!stbi__parse_entropy_coded_data(j))
            return 0;
         if (j->marker == STBI__MARKER_none)
         {
            // handle 0s at the end of image data from IP Kamera 9060
            while (!stbi__at_eof(j->s))
            {
               int x = stbi__get8(j->s);
               if (x == 255)
               {
                  j->marker = stbi__get8(j->s);
                  break;
               }
            }
            // if we reach eof without hitting a marker, stbi__get_marker() below will fail and we'll eventually return 0
         }
      }
      else if (stbi__DNL(m))
      {
         int Ld = stbi__get16be(j->s);
         stbi__uint32 NL = stbi__get16be(j->s);
         if (Ld != 4)
            return stbi__err("bad DNL len", "Corrupt JPEG");
         if (NL != j->s->img_y)
            return stbi__err("bad DNL height", "Corrupt JPEG");
      }
      else
      {
         if (!stbi__process_marker(j, m))
            return 0;
      }
      m = stbi__get_marker(j);
   }
   if (j->progressive)
      stbi__jpeg_finish(j);
   return 1;
}

// static jfif-centered resampling (across block boundaries)

typedef stbi_uc *(*resample_row_func)(stbi_uc *out, stbi_uc *in0, stbi_uc *in1,
                                      int w, int hs);

#define stbi__div4(x) ((stbi_uc)((x) >> 2))

static stbi_uc *resample_row_1(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
{
   STBI_NOTUSED(out);
   STBI_NOTUSED(in_far);
   STBI_NOTUSED(w);
   STBI_NOTUSED(hs);
   return in_near;
}

static stbi_uc *stbi__resample_row_v_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
{
   // need to generate two samples vertically for every one in input
   int i;
   STBI_NOTUSED(hs);
   for (i = 0; i < w; ++i)
      out[i] = stbi__div4(3 * in_near[i] + in_far[i] + 2);
   return out;
}

static stbi_uc *stbi__resample_row_h_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
{
   // need to generate two samples horizontally for every one in input
   int i;
   stbi_uc *input = in_near;

   if (w == 1)
   {
      // if only one sample, can't do any interpolation
      out[0] = out[1] = input[0];
      return out;
   }

   out[0] = input[0];
   out[1] = stbi__div4(input[0] * 3 + input[1] + 2);
   for (i = 1; i < w - 1; ++i)
   {
      int n = 3 * input[i] + 2;
      out[i * 2 + 0] = stbi__div4(n + input[i - 1]);
      out[i * 2 + 1] = stbi__div4(n + input[i + 1]);
   }
   out[i * 2 + 0] = stbi__div4(input[w - 2] * 3 + input[w - 1] + 2);
   out[i * 2 + 1] = input[w - 1];

   STBI_NOTUSED(in_far);
   STBI_NOTUSED(hs);

   return out;
}

#define stbi__div16(x) ((stbi_uc)((x) >> 4))

static stbi_uc *stbi__resample_row_hv_2(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
{
   // need to generate 2x2 samples for every one in input
   int i, t0, t1;
   if (w == 1)
   {
      out[0] = out[1] = stbi__div4(3 * in_near[0] + in_far[0] + 2);
      return out;
   }

   t1 = 3 * in_near[0] + in_far[0];
   out[0] = stbi__div4(t1 + 2);
   for (i = 1; i < w; ++i)
   {
      t0 = t1;
      t1 = 3 * in_near[i] + in_far[i];
      out[i * 2 - 1] = stbi__div16(3 * t0 + t1 + 8);
      out[i * 2] = stbi__div16(3 * t1 + t0 + 8);
   }
   out[w * 2 - 1] = stbi__div4(t1 + 2);

   STBI_NOTUSED(hs);

   return out;
}

#if defined(STBI_SSE2) || defined(STBI_NEON)
static stbi_uc *stbi__resample_row_hv_2_simd(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
{
   // need to generate 2x2 samples for every one in input
   int i = 0, t0, t1;

   if (w == 1)
   {
      out[0] = out[1] = stbi__div4(3 * in_near[0] + in_far[0] + 2);
      return out;
   }

   t1 = 3 * in_near[0] + in_far[0];
   // process groups of 8 pixels for as long as we can.
   // note we can't handle the last pixel in a row in this loop
   // because we need to handle the filter boundary conditions.
   for (; i < ((w - 1) & ~7); i += 8)
   {
#if defined(STBI_SSE2)
      // load and perform the vertical filtering pass
      // this uses 3*x + y = 4*x + (y - x)
      __m128i zero = _mm_setzero_si128();
      __m128i farb = _mm_loadl_epi64((__m128i *)(in_far + i));
      __m128i nearb = _mm_loadl_epi64((__m128i *)(in_near + i));
      __m128i farw = _mm_unpacklo_epi8(farb, zero);
      __m128i nearw = _mm_unpacklo_epi8(nearb, zero);
      __m128i diff = _mm_sub_epi16(farw, nearw);
      __m128i nears = _mm_slli_epi16(nearw, 2);
      __m128i curr = _mm_add_epi16(nears, diff); // current row

      // horizontal filter works the same based on shifted vers of current
      // row. "prev" is current row shifted right by 1 pixel; we need to
      // insert the previous pixel value (from t1).
      // "next" is current row shifted left by 1 pixel, with first pixel
      // of next block of 8 pixels added in.
      __m128i prv0 = _mm_slli_si128(curr, 2);
      __m128i nxt0 = _mm_srli_si128(curr, 2);
      __m128i prev = _mm_insert_epi16(prv0, t1, 0);
      __m128i next = _mm_insert_epi16(nxt0, 3 * in_near[i + 8] + in_far[i + 8], 7);

      // horizontal filter, polyphase implementation since it's convenient:
      // even pixels = 3*cur + prev = cur*4 + (prev - cur)
      // odd  pixels = 3*cur + next = cur*4 + (next - cur)
      // note the shared term.
      __m128i bias = _mm_set1_epi16(8);
      __m128i curs = _mm_slli_epi16(curr, 2);
      __m128i prvd = _mm_sub_epi16(prev, curr);
      __m128i nxtd = _mm_sub_epi16(next, curr);
      __m128i curb = _mm_add_epi16(curs, bias);
      __m128i even = _mm_add_epi16(prvd, curb);
      __m128i odd = _mm_add_epi16(nxtd, curb);

      // interleave even and odd pixels, then undo scaling.
      __m128i int0 = _mm_unpacklo_epi16(even, odd);
      __m128i int1 = _mm_unpackhi_epi16(even, odd);
      __m128i de0 = _mm_srli_epi16(int0, 4);
      __m128i de1 = _mm_srli_epi16(int1, 4);

      // pack and write output
      __m128i outv = _mm_packus_epi16(de0, de1);
      _mm_storeu_si128((__m128i *)(out + i * 2), outv);
#elif defined(STBI_NEON)
      // load and perform the vertical filtering pass
      // this uses 3*x + y = 4*x + (y - x)
      uint8x8_t farb = vld1_u8(in_far + i);
      uint8x8_t nearb = vld1_u8(in_near + i);
      int16x8_t diff = vreinterpretq_s16_u16(vsubl_u8(farb, nearb));
      int16x8_t nears = vreinterpretq_s16_u16(vshll_n_u8(nearb, 2));
      int16x8_t curr = vaddq_s16(nears, diff); // current row

      // horizontal filter works the same based on shifted vers of current
      // row. "prev" is current row shifted right by 1 pixel; we need to
      // insert the previous pixel value (from t1).
      // "next" is current row shifted left by 1 pixel, with first pixel
      // of next block of 8 pixels added in.
      int16x8_t prv0 = vextq_s16(curr, curr, 7);
      int16x8_t nxt0 = vextq_s16(curr, curr, 1);
      int16x8_t prev = vsetq_lane_s16(t1, prv0, 0);
      int16x8_t next = vsetq_lane_s16(3 * in_near[i + 8] + in_far[i + 8], nxt0, 7);

      // horizontal filter, polyphase implementation since it's convenient:
      // even pixels = 3*cur + prev = cur*4 + (prev - cur)
      // odd  pixels = 3*cur + next = cur*4 + (next - cur)
      // note the shared term.
      int16x8_t curs = vshlq_n_s16(curr, 2);
      int16x8_t prvd = vsubq_s16(prev, curr);
      int16x8_t nxtd = vsubq_s16(next, curr);
      int16x8_t even = vaddq_s16(curs, prvd);
      int16x8_t odd = vaddq_s16(curs, nxtd);

      // undo scaling and round, then store with even/odd phases interleaved
      uint8x8x2_t o;
      o.val[0] = vqrshrun_n_s16(even, 4);
      o.val[1] = vqrshrun_n_s16(odd, 4);
      vst2_u8(out + i * 2, o);
#endif

      // "previous" value for next iter
      t1 = 3 * in_near[i + 7] + in_far[i + 7];
   }

   t0 = t1;
   t1 = 3 * in_near[i] + in_far[i];
   out[i * 2] = stbi__div16(3 * t1 + t0 + 8);

   for (++i; i < w; ++i)
   {
      t0 = t1;
      t1 = 3 * in_near[i] + in_far[i];
      out[i * 2 - 1] = stbi__div16(3 * t0 + t1 + 8);
      out[i * 2] = stbi__div16(3 * t1 + t0 + 8);
   }
   out[w * 2 - 1] = stbi__div4(t1 + 2);

   STBI_NOTUSED(hs);

   return out;
}
#endif

static stbi_uc *stbi__resample_row_generic(stbi_uc *out, stbi_uc *in_near, stbi_uc *in_far, int w, int hs)
{
   // resample with nearest-neighbor
   int i, j;
   STBI_NOTUSED(in_far);
   for (i = 0; i < w; ++i)
      for (j = 0; j < hs; ++j)
         out[i * hs + j] = in_near[i];
   return out;
}

// this is a reduced-precision calculation of YCbCr-to-RGB introduced
// to make sure the code produces the same results in both SIMD and scalar
#define stbi__float2fixed(x) (((int)((x)*4096.0f + 0.5f)) << 8)
static void stbi__YCbCr_to_RGB_row(stbi_uc *out, const stbi_uc *y, const stbi_uc *pcb, const stbi_uc *pcr, int count, int step)
{
   int i;
   for (i = 0; i < count; ++i)
   {
      int y_fixed = (y[i] << 20) + (1 << 19); // rounding
      int r, g, b;
      int cr = pcr[i] - 128;
      int cb = pcb[i] - 128;
      r = y_fixed + cr * stbi__float2fixed(1.40200f);
      g = y_fixed + (cr * -stbi__float2fixed(0.71414f)) + ((cb * -stbi__float2fixed(0.34414f)) & 0xffff0000);
      b = y_fixed + cb * stbi__float2fixed(1.77200f);
      r >>= 20;
      g >>= 20;
      b >>= 20;
      if ((unsigned)r > 255)
      {
         if (r < 0)
            r = 0;
         else
            r = 255;
      }
      if ((unsigned)g > 255)
      {
         if (g < 0)
            g = 0;
         else
            g = 255;
      }
      if ((unsigned)b > 255)
      {
         if (b < 0)
            b = 0;
         else
            b = 255;
      }
      out[0] = (stbi_uc)r;
      out[1] = (stbi_uc)g;
      out[2] = (stbi_uc)b;
      out[3] = 255;
      out += step;
   }
}

#if defined(STBI_SSE2) || defined(STBI_NEON)
static void stbi__YCbCr_to_RGB_simd(stbi_uc *out, stbi_uc const *y, stbi_uc const *pcb, stbi_uc const *pcr, int count, int step)
{
   int i = 0;

#ifdef STBI_SSE2
   // step == 3 is pretty ugly on the final interleave, and i'm not convinced
   // it's useful in practice (you wouldn't use it for textures, for example).
   // so just accelerate step == 4 case.
   if (step == 4)
   {
      // this is a fairly straightforward implementation and not super-optimized.
      __m128i signflip = _mm_set1_epi8(-0x80);
      __m128i cr_const0 = _mm_set1_epi16((short)(1.40200f * 4096.0f + 0.5f));
      __m128i cr_const1 = _mm_set1_epi16(-(short)(0.71414f * 4096.0f + 0.5f));
      __m128i cb_const0 = _mm_set1_epi16(-(short)(0.34414f * 4096.0f + 0.5f));
      __m128i cb_const1 = _mm_set1_epi16((short)(1.77200f * 4096.0f + 0.5f));
      __m128i y_bias = _mm_set1_epi8((char)(unsigned char)128);
      __m128i xw = _mm_set1_epi16(255); // alpha channel

      for (; i + 7 < count; i += 8)
      {
         // load
         __m128i y_bytes = _mm_loadl_epi64((__m128i *)(y + i));
         __m128i cr_bytes = _mm_loadl_epi64((__m128i *)(pcr + i));
         __m128i cb_bytes = _mm_loadl_epi64((__m128i *)(pcb + i));
         __m128i cr_biased = _mm_xor_si128(cr_bytes, signflip); // -128
         __m128i cb_biased = _mm_xor_si128(cb_bytes, signflip); // -128

         // unpack to short (and left-shift cr, cb by 8)
         __m128i yw = _mm_unpacklo_epi8(y_bias, y_bytes);
         __m128i crw = _mm_unpacklo_epi8(_mm_setzero_si128(), cr_biased);
         __m128i cbw = _mm_unpacklo_epi8(_mm_setzero_si128(), cb_biased);

         // color transform
         __m128i yws = _mm_srli_epi16(yw, 4);
         __m128i cr0 = _mm_mulhi_epi16(cr_const0, crw);
         __m128i cb0 = _mm_mulhi_epi16(cb_const0, cbw);
         __m128i cb1 = _mm_mulhi_epi16(cbw, cb_const1);
         __m128i cr1 = _mm_mulhi_epi16(crw, cr_const1);
         __m128i rws = _mm_add_epi16(cr0, yws);
         __m128i gwt = _mm_add_epi16(cb0, yws);
         __m128i bws = _mm_add_epi16(yws, cb1);
         __m128i gws = _mm_add_epi16(gwt, cr1);

         // descale
         __m128i rw = _mm_srai_epi16(rws, 4);
         __m128i bw = _mm_srai_epi16(bws, 4);
         __m128i gw = _mm_srai_epi16(gws, 4);

         // back to byte, set up for transpose
         __m128i brb = _mm_packus_epi16(rw, bw);
         __m128i gxb = _mm_packus_epi16(gw, xw);

         // transpose to interleave channels
         __m128i t0 = _mm_unpacklo_epi8(brb, gxb);
         __m128i t1 = _mm_unpackhi_epi8(brb, gxb);
         __m128i o0 = _mm_unpacklo_epi16(t0, t1);
         __m128i o1 = _mm_unpackhi_epi16(t0, t1);

         // store
         _mm_storeu_si128((__m128i *)(out + 0), o0);
         _mm_storeu_si128((__m128i *)(out + 16), o1);
         out += 32;
      }
   }
#endif

#ifdef STBI_NEON
   // in this version, step=3 support would be easy to add. but is there demand?
   if (step == 4)
   {
      // this is a fairly straightforward implementation and not super-optimized.
      uint8x8_t signflip = vdup_n_u8(0x80);
      int16x8_t cr_const0 = vdupq_n_s16((short)(1.40200f * 4096.0f + 0.5f));
      int16x8_t cr_const1 = vdupq_n_s16(-(short)(0.71414f * 4096.0f + 0.5f));
      int16x8_t cb_const0 = vdupq_n_s16(-(short)(0.34414f * 4096.0f + 0.5f));
      int16x8_t cb_const1 = vdupq_n_s16((short)(1.77200f * 4096.0f + 0.5f));

      for (; i + 7 < count; i += 8)
      {
         // load
         uint8x8_t y_bytes = vld1_u8(y + i);
         uint8x8_t cr_bytes = vld1_u8(pcr + i);
         uint8x8_t cb_bytes = vld1_u8(pcb + i);
         int8x8_t cr_biased = vreinterpret_s8_u8(vsub_u8(cr_bytes, signflip));
         int8x8_t cb_biased = vreinterpret_s8_u8(vsub_u8(cb_bytes, signflip));

         // expand to s16
         int16x8_t yws = vreinterpretq_s16_u16(vshll_n_u8(y_bytes, 4));
         int16x8_t crw = vshll_n_s8(cr_biased, 7);
         int16x8_t cbw = vshll_n_s8(cb_biased, 7);

         // color transform
         int16x8_t cr0 = vqdmulhq_s16(crw, cr_const0);
         int16x8_t cb0 = vqdmulhq_s16(cbw, cb_const0);
         int16x8_t cr1 = vqdmulhq_s16(crw, cr_const1);
         int16x8_t cb1 = vqdmulhq_s16(cbw, cb_const1);
         int16x8_t rws = vaddq_s16(yws, cr0);
         int16x8_t gws = vaddq_s16(vaddq_s16(yws, cb0), cr1);
         int16x8_t bws = vaddq_s16(yws, cb1);

         // undo scaling, round, convert to byte
         uint8x8x4_t o;
         o.val[0] = vqrshrun_n_s16(rws, 4);
         o.val[1] = vqrshrun_n_s16(gws, 4);
         o.val[2] = vqrshrun_n_s16(bws, 4);
         o.val[3] = vdup_n_u8(255);

         // store, interleaving r/g/b/a
         vst4_u8(out, o);
         out += 8 * 4;
      }
   }
#endif

   for (; i < count; ++i)
   {
      int y_fixed = (y[i] << 20) + (1 << 19); // rounding
      int r, g, b;
      int cr = pcr[i] - 128;
      int cb = pcb[i] - 128;
      r = y_fixed + cr * stbi__float2fixed(1.40200f);
      g = y_fixed + cr * -stbi__float2fixed(0.71414f) + ((cb * -stbi__float2fixed(0.34414f)) & 0xffff0000);
      b = y_fixed + cb * stbi__float2fixed(1.77200f);
      r >>= 20;
      g >>= 20;
      b >>= 20;
      if ((unsigned)r > 255)
      {
         if (r < 0)
            r = 0;
         else
            r = 255;
      }
      if ((unsigned)g > 255)
      {
         if (g < 0)
            g = 0;
         else
            g = 255;
      }
      if ((unsigned)b > 255)
      {
         if (b < 0)
            b = 0;
         else
            b = 255;
      }
      out[0] = (stbi_uc)r;
      out[1] = (stbi_uc)g;
      out[2] = (stbi_uc)b;
      out[3] = 255;
      out += step;
   }
}
#endif

// set up the kernels
static void stbi__setup_jpeg(stbi__jpeg *j)
{
   j->idct_block_kernel = stbi__idct_block;
   j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_row;
   j->resample_row_hv_2_kernel = stbi__resample_row_hv_2;

#ifdef STBI_SSE2
   if (stbi__sse2_available())
   {
      j->idct_block_kernel = stbi__idct_simd;
      j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
      j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
   }
#endif

#ifdef STBI_NEON
   j->idct_block_kernel = stbi__idct_simd;
   j->YCbCr_to_RGB_kernel = stbi__YCbCr_to_RGB_simd;
   j->resample_row_hv_2_kernel = stbi__resample_row_hv_2_simd;
#endif
}

// clean up the temporary component buffers
static void stbi__cleanup_jpeg(stbi__jpeg *j)
{
   stbi__free_jpeg_components(j, j->s->img_n, 0);
}

typedef struct
{
   resample_row_func resample;
   stbi_uc *line0, *line1;
   int hs, vs;  // expansion factor in each axis
   int w_lores; // horizontal pixels pre-expansion
   int ystep;   // how far through vertical expansion we are
   int ypos;    // which pre-expansion row we're on
} stbi__resample;

// fast 0..255 * 0..255 => 0..255 rounded multiplication
static stbi_uc stbi__blinn_8x8(stbi_uc x, stbi_uc y)
{
   unsigned int t = x * y + 128;
   return (stbi_uc)((t + (t >> 8)) >> 8);
}

static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp, int req_comp)
{
   int n, decode_n, is_rgb;
   z->s->img_n = 0; // make stbi__cleanup_jpeg safe

   // validate req_comp
   if (req_comp < 0 || req_comp > 4)
      return stbi__errpuc("bad req_comp", "Internal error");

   // load a jpeg image from whichever source, but leave in YCbCr format
   if (!stbi__decode_jpeg_image(z))
   {
      stbi__cleanup_jpeg(z);
      return NULL;
   }

   // determine actual number of components to generate
   n = req_comp ? req_comp : z->s->img_n >= 3 ? 3 : 1;

   is_rgb = z->s->img_n == 3 && (z->rgb == 3 || (z->app14_color_transform == 0 && !z->jfif));

   if (z->s->img_n == 3 && n < 3 && !is_rgb)
      decode_n = 1;
   else
      decode_n = z->s->img_n;

   // resample and color-convert
   {
      int k;
      unsigned int i, j;
      stbi_uc *output;
      stbi_uc *coutput[4] = {NULL, NULL, NULL, NULL};

      stbi__resample res_comp[4];

      for (k = 0; k < decode_n; ++k)
      {
         stbi__resample *r = &res_comp[k];

         // allocate line buffer big enough for upsampling off the edges
         // with upsample factor of 4
         z->img_comp[k].linebuf = (stbi_uc *)stbi__malloc(z->s->img_x + 3);
         if (!z->img_comp[k].linebuf)
         {
            stbi__cleanup_jpeg(z);
            return stbi__errpuc("outofmem", "Out of memory");
         }

         r->hs = z->img_h_max / z->img_comp[k].h;
         r->vs = z->img_v_max / z->img_comp[k].v;
         r->ystep = r->vs >> 1;
         r->w_lores = (z->s->img_x + r->hs - 1) / r->hs;
         r->ypos = 0;
         r->line0 = r->line1 = z->img_comp[k].data;

         if (r->hs == 1 && r->vs == 1)
            r->resample = resample_row_1;
         else if (r->hs == 1 && r->vs == 2)
            r->resample = stbi__resample_row_v_2;
         else if (r->hs == 2 && r->vs == 1)
            r->resample = stbi__resample_row_h_2;
         else if (r->hs == 2 && r->vs == 2)
            r->resample = z->resample_row_hv_2_kernel;
         else
            r->resample = stbi__resample_row_generic;
      }

      // can't error after this so, this is safe
      output = (stbi_uc *)stbi__malloc_mad3(n, z->s->img_x, z->s->img_y, 1);
      if (!output)
      {
         stbi__cleanup_jpeg(z);
         return stbi__errpuc("outofmem", "Out of memory");
      }

      // now go ahead and resample
      for (j = 0; j < z->s->img_y; ++j)
      {
         stbi_uc *out = output + n * z->s->img_x * j;
         for (k = 0; k < decode_n; ++k)
         {
            stbi__resample *r = &res_comp[k];
            int y_bot = r->ystep >= (r->vs >> 1);
            coutput[k] = r->resample(z->img_comp[k].linebuf,
                                     y_bot ? r->line1 : r->line0,
                                     y_bot ? r->line0 : r->line1,
                                     r->w_lores, r->hs);
            if (++r->ystep >= r->vs)
            {
               r->ystep = 0;
               r->line0 = r->line1;
               if (++r->ypos < z->img_comp[k].y)
                  r->line1 += z->img_comp[k].w2;
            }
         }
         if (n >= 3)
         {
            stbi_uc *y = coutput[0];
            if (z->s->img_n == 3)
            {
               if (is_rgb)
               {
                  for (i = 0; i < z->s->img_x; ++i)
                  {
                     out[0] = y[i];
                     out[1] = coutput[1][i];
                     out[2] = coutput[2][i];
                     out[3] = 255;
                     out += n;
                  }
               }
               else
               {
                  z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
               }
            }
            else if (z->s->img_n == 4)
            {
               if (z->app14_color_transform == 0)
               { // CMYK
                  for (i = 0; i < z->s->img_x; ++i)
                  {
                     stbi_uc m = coutput[3][i];
                     out[0] = stbi__blinn_8x8(coutput[0][i], m);
                     out[1] = stbi__blinn_8x8(coutput[1][i], m);
                     out[2] = stbi__blinn_8x8(coutput[2][i], m);
                     out[3] = 255;
                     out += n;
                  }
               }
               else if (z->app14_color_transform == 2)
               { // YCCK
                  z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
                  for (i = 0; i < z->s->img_x; ++i)
                  {
                     stbi_uc m = coutput[3][i];
                     out[0] = stbi__blinn_8x8(255 - out[0], m);
                     out[1] = stbi__blinn_8x8(255 - out[1], m);
                     out[2] = stbi__blinn_8x8(255 - out[2], m);
                     out += n;
                  }
               }
               else
               { // YCbCr + alpha?  Ignore the fourth channel for now
                  z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
               }
            }
            else
               for (i = 0; i < z->s->img_x; ++i)
               {
                  out[0] = out[1] = out[2] = y[i];
                  out[3] = 255; // not used if n==3
                  out += n;
               }
         }
         else
         {
            if (is_rgb)
            {
               if (n == 1)
                  for (i = 0; i < z->s->img_x; ++i)
                     *out++ = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]);
               else
               {
                  for (i = 0; i < z->s->img_x; ++i, out += 2)
                  {
                     out[0] = stbi__compute_y(coutput[0][i], coutput[1][i], coutput[2][i]);
                     out[1] = 255;
                  }
               }
            }
            else if (z->s->img_n == 4 && z->app14_color_transform == 0)
            {
               for (i = 0; i < z->s->img_x; ++i)
               {
                  stbi_uc m = coutput[3][i];
                  stbi_uc r = stbi__blinn_8x8(coutput[0][i], m);
                  stbi_uc g = stbi__blinn_8x8(coutput[1][i], m);
                  stbi_uc b = stbi__blinn_8x8(coutput[2][i], m);
                  out[0] = stbi__compute_y(r, g, b);
                  out[1] = 255;
                  out += n;
               }
            }
            else if (z->s->img_n == 4 && z->app14_color_transform == 2)
            {
               for (i = 0; i < z->s->img_x; ++i)
               {
                  out[0] = stbi__blinn_8x8(255 - coutput[0][i], coutput[3][i]);
                  out[1] = 255;
                  out += n;
               }
            }
            else
            {
               stbi_uc *y = coutput[0];
               if (n == 1)
                  for (i = 0; i < z->s->img_x; ++i)
                     out[i] = y[i];
               else
                  for (i = 0; i < z->s->img_x; ++i)
                  {
                     *out++ = y[i];
                     *out++ = 255;
                  }
            }
         }
      }
      stbi__cleanup_jpeg(z);
      *out_x = z->s->img_x;
      *out_y = z->s->img_y;
      if (comp)
         *comp = z->s->img_n >= 3 ? 3 : 1; // report original components, not output
      return output;
   }
}

static void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
{
   unsigned char *result;
   stbi__jpeg *j = (stbi__jpeg *)stbi__malloc(sizeof(stbi__jpeg));
   STBI_NOTUSED(ri);
   j->s = s;
   stbi__setup_jpeg(j);
   result = load_jpeg_image(j, x, y, comp, req_comp);
   STBI_FREE(j);
   return result;
}

static int stbi__jpeg_test(stbi__context *s)
{
   int r;
   stbi__jpeg *j = (stbi__jpeg *)stbi__malloc(sizeof(stbi__jpeg));
   j->s = s;
   stbi__setup_jpeg(j);
   r = stbi__decode_jpeg_header(j, STBI__SCAN_type);
   stbi__rewind(s);
   STBI_FREE(j);
   return r;
}

static int stbi__jpeg_info_raw(stbi__jpeg *j, int *x, int *y, int *comp)
{
   if (!stbi__decode_jpeg_header(j, STBI__SCAN_header))
   {
      stbi__rewind(j->s);
      return 0;
   }
   if (x)
      *x = j->s->img_x;
   if (y)
      *y = j->s->img_y;
   if (comp)
      *comp = j->s->img_n >= 3 ? 3 : 1;
   return 1;
}

static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp)
{
   int result;
   stbi__jpeg *j = (stbi__jpeg *)(stbi__malloc(sizeof(stbi__jpeg)));
   j->s = s;
   result = stbi__jpeg_info_raw(j, x, y, comp);
   STBI_FREE(j);
   return result;
}
#endif

// public domain zlib decode    v0.2  Sean Barrett 2006-11-18
//    simple implementation
//      - all input must be provided in an upfront buffer
//      - all output is written to a single output buffer (can malloc/realloc)
//    performance
//      - fast huffman

#ifndef STBI_NO_ZLIB

// fast-way is faster to check than jpeg huffman, but slow way is slower
#define STBI__ZFAST_BITS 9 // accelerate all cases in default tables
#define STBI__ZFAST_MASK ((1 << STBI__ZFAST_BITS) - 1)

// zlib-style huffman encoding
// (jpegs packs from left, zlib from right, so can't share code)
typedef struct
{
   stbi__uint16 fast[1 << STBI__ZFAST_BITS];
   stbi__uint16 firstcode[16];
   int maxcode[17];
   stbi__uint16 firstsymbol[16];
   stbi_uc size[288];
   stbi__uint16 value[288];
} stbi__zhuffman;

stbi_inline static int stbi__bitreverse16(int n)
{
   n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1);
   n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2);
   n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4);
   n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8);
   return n;
}

stbi_inline static int stbi__bit_reverse(int v, int bits)
{
   STBI_ASSERT(bits <= 16);
   // to bit reverse n bits, reverse 16 and shift
   // e.g. 11 bits, bit reverse and shift away 5
   return stbi__bitreverse16(v) >> (16 - bits);
}

static int stbi__zbuild_huffman(stbi__zhuffman *z, const stbi_uc *sizelist, int num)
{
   int i, k = 0;
   int code, next_code[16], sizes[17];

   // DEFLATE spec for generating codes
   memset(sizes, 0, sizeof(sizes));
   memset(z->fast, 0, sizeof(z->fast));
   for (i = 0; i < num; ++i)
      ++sizes[sizelist[i]];
   sizes[0] = 0;
   for (i = 1; i < 16; ++i)
      if (sizes[i] > (1 << i))
         return stbi__err("bad sizes", "Corrupt PNG");
   code = 0;
   for (i = 1; i < 16; ++i)
   {
      next_code[i] = code;
      z->firstcode[i] = (stbi__uint16)code;
      z->firstsymbol[i] = (stbi__uint16)k;
      code = (code + sizes[i]);
      if (sizes[i])
         if (code - 1 >= (1 << i))
            return stbi__err("bad codelengths", "Corrupt PNG");
      z->maxcode[i] = code << (16 - i); // preshift for inner loop
      code <<= 1;
      k += sizes[i];
   }
   z->maxcode[16] = 0x10000; // sentinel
   for (i = 0; i < num; ++i)
   {
      int s = sizelist[i];
      if (s)
      {
         int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s];
         stbi__uint16 fastv = (stbi__uint16)((s << 9) | i);
         z->size[c] = (stbi_uc)s;
         z->value[c] = (stbi__uint16)i;
         if (s <= STBI__ZFAST_BITS)
         {
            int j = stbi__bit_reverse(next_code[s], s);
            while (j < (1 << STBI__ZFAST_BITS))
            {
               z->fast[j] = fastv;
               j += (1 << s);
            }
         }
         ++next_code[s];
      }
   }
   return 1;
}

// zlib-from-memory implementation for PNG reading
//    because PNG allows splitting the zlib stream arbitrarily,
//    and it's annoying structurally to have PNG call ZLIB call PNG,
//    we require PNG read all the IDATs and combine them into a single
//    memory buffer

typedef struct
{
   stbi_uc *zbuffer, *zbuffer_end;
   int num_bits;
   stbi__uint32 code_buffer;

   char *zout;
   char *zout_start;
   char *zout_end;
   int z_expandable;

   stbi__zhuffman z_length, z_distance;
} stbi__zbuf;

stbi_inline static stbi_uc stbi__zget8(stbi__zbuf *z)
{
   if (z->zbuffer >= z->zbuffer_end)
      return 0;
   return *z->zbuffer++;
}

static void stbi__fill_bits(stbi__zbuf *z)
{
   do
   {
      STBI_ASSERT(z->code_buffer < (1U << z->num_bits));
      z->code_buffer |= (unsigned int)stbi__zget8(z) << z->num_bits;
      z->num_bits += 8;
   } while (z->num_bits <= 24);
}

stbi_inline static unsigned int stbi__zreceive(stbi__zbuf *z, int n)
{
   unsigned int k;
   if (z->num_bits < n)
      stbi__fill_bits(z);
   k = z->code_buffer & ((1 << n) - 1);
   z->code_buffer >>= n;
   z->num_bits -= n;
   return k;
}

static int stbi__zhuffman_decode_slowpath(stbi__zbuf *a, stbi__zhuffman *z)
{
   int b, s, k;
   // not resolved by fast table, so compute it the slow way
   // use jpeg approach, which requires MSbits at top
   k = stbi__bit_reverse(a->code_buffer, 16);
   for (s = STBI__ZFAST_BITS + 1;; ++s)
      if (k < z->maxcode[s])
         break;
   if (s == 16)
      return -1; // invalid code!
   // code size is s, so:
   b = (k >> (16 - s)) - z->firstcode[s] + z->firstsymbol[s];
   STBI_ASSERT(z->size[b] == s);
   a->code_buffer >>= s;
   a->num_bits -= s;
   return z->value[b];
}

stbi_inline static int stbi__zhuffman_decode(stbi__zbuf *a, stbi__zhuffman *z)
{
   int b, s;
   if (a->num_bits < 16)
      stbi__fill_bits(a);
   b = z->fast[a->code_buffer & STBI__ZFAST_MASK];
   if (b)
   {
      s = b >> 9;
      a->code_buffer >>= s;
      a->num_bits -= s;
      return b & 511;
   }
   return stbi__zhuffman_decode_slowpath(a, z);
}

static int stbi__zexpand(stbi__zbuf *z, char *zout, int n) // need to make room for n bytes
{
   char *q;
   int cur, limit, old_limit;
   z->zout = zout;
   if (!z->z_expandable)
      return stbi__err("output buffer limit", "Corrupt PNG");
   cur = (int)(z->zout - z->zout_start);
   limit = old_limit = (int)(z->zout_end - z->zout_start);
   while (cur + n > limit)
      limit *= 2;
   q = (char *)STBI_REALLOC_SIZED(z->zout_start, old_limit, limit);
   STBI_NOTUSED(old_limit);
   if (q == NULL)
      return stbi__err("outofmem", "Out of memory");
   z->zout_start = q;
   z->zout = q + cur;
   z->zout_end = q + limit;
   return 1;
}

static const int stbi__zlength_base[31] = {
    3, 4, 5, 6, 7, 8, 9, 10, 11, 13,
    15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
    67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};

static const int stbi__zlength_extra[31] =
    {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 0, 0};

static const int stbi__zdist_base[32] = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
                                         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 0, 0};

static const int stbi__zdist_extra[32] =
    {0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13};

static int stbi__parse_huffman_block(stbi__zbuf *a)
{
   char *zout = a->zout;
   for (;;)
   {
      int z = stbi__zhuffman_decode(a, &a->z_length);
      if (z < 256)
      {
         if (z < 0)
            return stbi__err("bad huffman code", "Corrupt PNG"); // error in huffman codes
         if (zout >= a->zout_end)
         {
            if (!stbi__zexpand(a, zout, 1))
               return 0;
            zout = a->zout;
         }
         *zout++ = (char)z;
      }
      else
      {
         stbi_uc *p;
         int len, dist;
         if (z == 256)
         {
            a->zout = zout;
            return 1;
         }
         z -= 257;
         len = stbi__zlength_base[z];
         if (stbi__zlength_extra[z])
            len += stbi__zreceive(a, stbi__zlength_extra[z]);
         z = stbi__zhuffman_decode(a, &a->z_distance);
         if (z < 0)
            return stbi__err("bad huffman code", "Corrupt PNG");
         dist = stbi__zdist_base[z];
         if (stbi__zdist_extra[z])
            dist += stbi__zreceive(a, stbi__zdist_extra[z]);
         if (zout - a->zout_start < dist)
            return stbi__err("bad dist", "Corrupt PNG");
         if (zout + len > a->zout_end)
         {
            if (!stbi__zexpand(a, zout, len))
               return 0;
            zout = a->zout;
         }
         p = (stbi_uc *)(zout - dist);
         if (dist == 1)
         { // run of one byte; common in images.
            stbi_uc v = *p;
            if (len)
            {
               do
                  *zout++ = v;
               while (--len);
            }
         }
         else
         {
            if (len)
            {
               do
                  *zout++ = *p++;
               while (--len);
            }
         }
      }
   }
}

static int stbi__compute_huffman_codes(stbi__zbuf *a)
{
   static const stbi_uc length_dezigzag[19] = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
   stbi__zhuffman z_codelength;
   stbi_uc lencodes[286 + 32 + 137]; //padding for maximum single op
   stbi_uc codelength_sizes[19];
   int i, n;

   int hlit = stbi__zreceive(a, 5) + 257;
   int hdist = stbi__zreceive(a, 5) + 1;
   int hclen = stbi__zreceive(a, 4) + 4;
   int ntot = hlit + hdist;

   memset(codelength_sizes, 0, sizeof(codelength_sizes));
   for (i = 0; i < hclen; ++i)
   {
      int s = stbi__zreceive(a, 3);
      codelength_sizes[length_dezigzag[i]] = (stbi_uc)s;
   }
   if (!stbi__zbuild_huffman(&z_codelength, codelength_sizes, 19))
      return 0;

   n = 0;
   while (n < ntot)
   {
      int c = stbi__zhuffman_decode(a, &z_codelength);
      if (c < 0 || c >= 19)
         return stbi__err("bad codelengths", "Corrupt PNG");
      if (c < 16)
         lencodes[n++] = (stbi_uc)c;
      else
      {
         stbi_uc fill = 0;
         if (c == 16)
         {
            c = stbi__zreceive(a, 2) + 3;
            if (n == 0)
               return stbi__err("bad codelengths", "Corrupt PNG");
            fill = lencodes[n - 1];
         }
         else if (c == 17)
            c = stbi__zreceive(a, 3) + 3;
         else
         {
            STBI_ASSERT(c == 18);
            c = stbi__zreceive(a, 7) + 11;
         }
         if (ntot - n < c)
            return stbi__err("bad codelengths", "Corrupt PNG");
         memset(lencodes + n, fill, c);
         n += c;
      }
   }
   if (n != ntot)
      return stbi__err("bad codelengths", "Corrupt PNG");
   if (!stbi__zbuild_huffman(&a->z_length, lencodes, hlit))
      return 0;
   if (!stbi__zbuild_huffman(&a->z_distance, lencodes + hlit, hdist))
      return 0;
   return 1;
}

static int stbi__parse_uncompressed_block(stbi__zbuf *a)
{
   stbi_uc header[4];
   int len, nlen, k;
   if (a->num_bits & 7)
      stbi__zreceive(a, a->num_bits & 7); // discard
   // drain the bit-packed data into header
   k = 0;
   while (a->num_bits > 0)
   {
      header[k++] = (stbi_uc)(a->code_buffer & 255); // suppress MSVC run-time check
      a->code_buffer >>= 8;
      a->num_bits -= 8;
   }
   STBI_ASSERT(a->num_bits == 0);
   // now fill header the normal way
   while (k < 4)
      header[k++] = stbi__zget8(a);
   len = header[1] * 256 + header[0];
   nlen = header[3] * 256 + header[2];
   if (nlen != (len ^ 0xffff))
      return stbi__err("zlib corrupt", "Corrupt PNG");
   if (a->zbuffer + len > a->zbuffer_end)
      return stbi__err("read past buffer", "Corrupt PNG");
   if (a->zout + len > a->zout_end)
      if (!stbi__zexpand(a, a->zout, len))
         return 0;
   memcpy(a->zout, a->zbuffer, len);
   a->zbuffer += len;
   a->zout += len;
   return 1;
}

static int stbi__parse_zlib_header(stbi__zbuf *a)
{
   int cmf = stbi__zget8(a);
   int cm = cmf & 15;
   /* int cinfo = cmf >> 4; */
   int flg = stbi__zget8(a);
   if ((cmf * 256 + flg) % 31 != 0)
      return stbi__err("bad zlib header", "Corrupt PNG"); // zlib spec
   if (flg & 32)
      return stbi__err("no preset dict", "Corrupt PNG"); // preset dictionary not allowed in png
   if (cm != 8)
      return stbi__err("bad compression", "Corrupt PNG"); // DEFLATE required for png
   // window = 1 << (8 + cinfo)... but who cares, we fully buffer output
   return 1;
}

static const stbi_uc stbi__zdefault_length[288] =
    {
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
        9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8};
static const stbi_uc stbi__zdefault_distance[32] =
    {
        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5};
/*
Init algorithm:
{
   int i;   // use <= to match clearly with spec
   for (i=0; i <= 143; ++i)     stbi__zdefault_length[i]   = 8;
   for (   ; i <= 255; ++i)     stbi__zdefault_length[i]   = 9;
   for (   ; i <= 279; ++i)     stbi__zdefault_length[i]   = 7;
   for (   ; i <= 287; ++i)     stbi__zdefault_length[i]   = 8;

   for (i=0; i <=  31; ++i)     stbi__zdefault_distance[i] = 5;
}
*/

static int stbi__parse_zlib(stbi__zbuf *a, int parse_header)
{
   int final, type;
   if (parse_header)
      if (!stbi__parse_zlib_header(a))
         return 0;
   a->num_bits = 0;
   a->code_buffer = 0;
   do
   {
      final = stbi__zreceive(a, 1);
      type = stbi__zreceive(a, 2);
      if (type == 0)
      {
         if (!stbi__parse_uncompressed_block(a))
            return 0;
      }
      else if (type == 3)
      {
         return 0;
      }
      else
      {
         if (type == 1)
         {
            // use fixed code lengths
            if (!stbi__zbuild_huffman(&a->z_length, stbi__zdefault_length, 288))
               return 0;
            if (!stbi__zbuild_huffman(&a->z_distance, stbi__zdefault_distance, 32))
               return 0;
         }
         else
         {
            if (!stbi__compute_huffman_codes(a))
               return 0;
         }
         if (!stbi__parse_huffman_block(a))
            return 0;
      }
   } while (!final);
   return 1;
}

static int stbi__do_zlib(stbi__zbuf *a, char *obuf, int olen, int exp, int parse_header)
{
   a->zout_start = obuf;
   a->zout = obuf;
   a->zout_end = obuf + olen;
   a->z_expandable = exp;

   return stbi__parse_zlib(a, parse_header);
}

STBIDEF char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen)
{
   stbi__zbuf a;
   char *p = (char *)stbi__malloc(initial_size);
   if (p == NULL)
      return NULL;
   a.zbuffer = (stbi_uc *)buffer;
   a.zbuffer_end = (stbi_uc *)buffer + len;
   if (stbi__do_zlib(&a, p, initial_size, 1, 1))
   {
      if (outlen)
         *outlen = (int)(a.zout - a.zout_start);
      return a.zout_start;
   }
   else
   {
      STBI_FREE(a.zout_start);
      return NULL;
   }
}

STBIDEF char *stbi_zlib_decode_malloc(char const *buffer, int len, int *outlen)
{
   return stbi_zlib_decode_malloc_guesssize(buffer, len, 16384, outlen);
}

STBIDEF char *stbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header)
{
   stbi__zbuf a;
   char *p = (char *)stbi__malloc(initial_size);
   if (p == NULL)
      return NULL;
   a.zbuffer = (stbi_uc *)buffer;
   a.zbuffer_end = (stbi_uc *)buffer + len;
   if (stbi__do_zlib(&a, p, initial_size, 1, parse_header))
   {
      if (outlen)
         *outlen = (int)(a.zout - a.zout_start);
      return a.zout_start;
   }
   else
   {
      STBI_FREE(a.zout_start);
      return NULL;
   }
}

STBIDEF int stbi_zlib_decode_buffer(char *obuffer, int olen, char const *ibuffer, int ilen)
{
   stbi__zbuf a;
   a.zbuffer = (stbi_uc *)ibuffer;
   a.zbuffer_end = (stbi_uc *)ibuffer + ilen;
   if (stbi__do_zlib(&a, obuffer, olen, 0, 1))
      return (int)(a.zout - a.zout_start);
   else
      return -1;
}

STBIDEF char *stbi_zlib_decode_noheader_malloc(char const *buffer, int len, int *outlen)
{
   stbi__zbuf a;
   char *p = (char *)stbi__malloc(16384);
   if (p == NULL)
      return NULL;
   a.zbuffer = (stbi_uc *)buffer;
   a.zbuffer_end = (stbi_uc *)buffer + len;
   if (stbi__do_zlib(&a, p, 16384, 1, 0))
   {
      if (outlen)
         *outlen = (int)(a.zout - a.zout_start);
      return a.zout_start;
   }
   else
   {
      STBI_FREE(a.zout_start);
      return NULL;
   }
}

STBIDEF int stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen)
{
   stbi__zbuf a;
   a.zbuffer = (stbi_uc *)ibuffer;
   a.zbuffer_end = (stbi_uc *)ibuffer + ilen;
   if (stbi__do_zlib(&a, obuffer, olen, 0, 0))
      return (int)(a.zout - a.zout_start);
   else
      return -1;
}
#endif

// public domain "baseline" PNG decoder   v0.10  Sean Barrett 2006-11-18
//    simple implementation
//      - only 8-bit samples
//      - no CRC checking
//      - allocates lots of intermediate memory
//        - avoids problem of streaming data between subsystems
//        - avoids explicit window management
//    performance
//      - uses stb_zlib, a PD zlib implementation with fast huffman decoding

#ifndef STBI_NO_PNG
typedef struct
{
   stbi__uint32 length;
   stbi__uint32 type;
} stbi__pngchunk;

static stbi__pngchunk stbi__get_chunk_header(stbi__context *s)
{
   stbi__pngchunk c;
   c.length = stbi__get32be(s);
   c.type = stbi__get32be(s);
   return c;
}

static int stbi__check_png_header(stbi__context *s)
{
   static const stbi_uc png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
   int i;
   for (i = 0; i < 8; ++i)
      if (stbi__get8(s) != png_sig[i])
         return stbi__err("bad png sig", "Not a PNG");
   return 1;
}

typedef struct
{
   stbi__context *s;
   stbi_uc *idata, *expanded, *out;
   int depth;
} stbi__png;

enum
{
   STBI__F_none = 0,
   STBI__F_sub = 1,
   STBI__F_up = 2,
   STBI__F_avg = 3,
   STBI__F_paeth = 4,
   // synthetic filters used for first scanline to avoid needing a dummy row of 0s
   STBI__F_avg_first,
   STBI__F_paeth_first
};

static stbi_uc first_row_filter[5] =
    {
        STBI__F_none,
        STBI__F_sub,
        STBI__F_none,
        STBI__F_avg_first,
        STBI__F_paeth_first};

static int stbi__paeth(int a, int b, int c)
{
   int p = a + b - c;
   int pa = abs(p - a);
   int pb = abs(p - b);
   int pc = abs(p - c);
   if (pa <= pb && pa <= pc)
      return a;
   if (pb <= pc)
      return b;
   return c;
}

static const stbi_uc stbi__depth_scale_table[9] = {0, 0xff, 0x55, 0, 0x11, 0, 0, 0, 0x01};

// create the png data from post-deflated data
static int stbi__create_png_image_raw(stbi__png *a, stbi_uc *raw, stbi__uint32 raw_len, int out_n, stbi__uint32 x, stbi__uint32 y, int depth, int color)
{
   int bytes = (depth == 16 ? 2 : 1);
   stbi__context *s = a->s;
   stbi__uint32 i, j, stride = x * out_n * bytes;
   stbi__uint32 img_len, img_width_bytes;
   int k;
   int img_n = s->img_n; // copy it into a local for later

   int output_bytes = out_n * bytes;
   int filter_bytes = img_n * bytes;
   int width = x;

   STBI_ASSERT(out_n == s->img_n || out_n == s->img_n + 1);
   a->out = (stbi_uc *)stbi__malloc_mad3(x, y, output_bytes, 0); // extra bytes to write off the end into
   if (!a->out)
      return stbi__err("outofmem", "Out of memory");

   if (!stbi__mad3sizes_valid(img_n, x, depth, 7))
      return stbi__err("too large", "Corrupt PNG");
   img_width_bytes = (((img_n * x * depth) + 7) >> 3);
   img_len = (img_width_bytes + 1) * y;

   // we used to check for exact match between raw_len and img_len on non-interlaced PNGs,
   // but issue #276 reported a PNG in the wild that had extra data at the end (all zeros),
   // so just check for raw_len < img_len always.
   if (raw_len < img_len)
      return stbi__err("not enough pixels", "Corrupt PNG");

   for (j = 0; j < y; ++j)
   {
      stbi_uc *cur = a->out + stride * j;
      stbi_uc *prior;
      int filter = *raw++;

      if (filter > 4)
         return stbi__err("invalid filter", "Corrupt PNG");

      if (depth < 8)
      {
         STBI_ASSERT(img_width_bytes <= x);
         cur += x * out_n - img_width_bytes; // store output to the rightmost img_len bytes, so we can decode in place
         filter_bytes = 1;
         width = img_width_bytes;
      }
      prior = cur - stride; // bugfix: need to compute this after 'cur +=' computation above

      // if first row, use special filter that doesn't sample previous row
      if (j == 0)
         filter = first_row_filter[filter];

      // handle first byte explicitly
      for (k = 0; k < filter_bytes; ++k)
      {
         switch (filter)
         {
         case STBI__F_none:
            cur[k] = raw[k];
            break;
         case STBI__F_sub:
            cur[k] = raw[k];
            break;
         case STBI__F_up:
            cur[k] = STBI__BYTECAST(raw[k] + prior[k]);
            break;
         case STBI__F_avg:
            cur[k] = STBI__BYTECAST(raw[k] + (prior[k] >> 1));
            break;
         case STBI__F_paeth:
            cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(0, prior[k], 0));
            break;
         case STBI__F_avg_first:
            cur[k] = raw[k];
            break;
         case STBI__F_paeth_first:
            cur[k] = raw[k];
            break;
         }
      }

      if (depth == 8)
      {
         if (img_n != out_n)
            cur[img_n] = 255; // first pixel
         raw += img_n;
         cur += out_n;
         prior += out_n;
      }
      else if (depth == 16)
      {
         if (img_n != out_n)
         {
            cur[filter_bytes] = 255;     // first pixel top byte
            cur[filter_bytes + 1] = 255; // first pixel bottom byte
         }
         raw += filter_bytes;
         cur += output_bytes;
         prior += output_bytes;
      }
      else
      {
         raw += 1;
         cur += 1;
         prior += 1;
      }

      // this is a little gross, so that we don't switch per-pixel or per-component
      if (depth < 8 || img_n == out_n)
      {
         int nk = (width - 1) * filter_bytes;
#define STBI__CASE(f) \
   case f:            \
      for (k = 0; k < nk; ++k)
         switch (filter)
         {
         // "none" filter turns into a memcpy here; make that explicit.
         case STBI__F_none:
            memcpy(cur, raw, nk);
            break;
            STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k - filter_bytes]); }
            break;
            STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); }
            break;
            STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k - filter_bytes]) >> 1)); }
            break;
            STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - filter_bytes], prior[k], prior[k - filter_bytes])); }
            break;
            STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k - filter_bytes] >> 1)); }
            break;
            STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - filter_bytes], 0, 0)); }
            break;
         }
#undef STBI__CASE
         raw += nk;
      }
      else
      {
         STBI_ASSERT(img_n + 1 == out_n);
#define STBI__CASE(f)                                                                                                        \
   case f:                                                                                                                   \
      for (i = x - 1; i >= 1; --i, cur[filter_bytes] = 255, raw += filter_bytes, cur += output_bytes, prior += output_bytes) \
         for (k = 0; k < filter_bytes; ++k)
         switch (filter)
         {
            STBI__CASE(STBI__F_none) { cur[k] = raw[k]; }
            break;
            STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k - output_bytes]); }
            break;
            STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); }
            break;
            STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k - output_bytes]) >> 1)); }
            break;
            STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - output_bytes], prior[k], prior[k - output_bytes])); }
            break;
            STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k - output_bytes] >> 1)); }
            break;
            STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + stbi__paeth(cur[k - output_bytes], 0, 0)); }
            break;
         }
#undef STBI__CASE

         // the loop above sets the high byte of the pixels' alpha, but for
         // 16 bit png files we also need the low byte set. we'll do that here.
         if (depth == 16)
         {
            cur = a->out + stride * j; // start at the beginning of the row again
            for (i = 0; i < x; ++i, cur += output_bytes)
            {
               cur[filter_bytes + 1] = 255;
            }
         }
      }
   }

   // we make a separate pass to expand bits to pixels; for performance,
   // this could run two scanlines behind the above code, so it won't
   // intefere with filtering but will still be in the cache.
   if (depth < 8)
   {
      for (j = 0; j < y; ++j)
      {
         stbi_uc *cur = a->out + stride * j;
         stbi_uc *in = a->out + stride * j + x * out_n - img_width_bytes;
         // unpack 1/2/4-bit into a 8-bit buffer. allows us to keep the common 8-bit path optimal at minimal cost for 1/2/4-bit
         // png guarante byte alignment, if width is not multiple of 8/4/2 we'll decode dummy trailing data that will be skipped in the later loop
         stbi_uc scale = (color == 0) ? stbi__depth_scale_table[depth] : 1; // scale grayscale values to 0..255 range

         // note that the final byte might overshoot and write more data than desired.
         // we can allocate enough data that this never writes out of memory, but it
         // could also overwrite the next scanline. can it overwrite non-empty data
         // on the next scanline? yes, consider 1-pixel-wide scanlines with 1-bit-per-pixel.
         // so we need to explicitly clamp the final ones

         if (depth == 4)
         {
            for (k = x * img_n; k >= 2; k -= 2, ++in)
            {
               *cur++ = scale * ((*in >> 4));
               *cur++ = scale * ((*in) & 0x0f);
            }
            if (k > 0)
               *cur++ = scale * ((*in >> 4));
         }
         else if (depth == 2)
         {
            for (k = x * img_n; k >= 4; k -= 4, ++in)
            {
               *cur++ = scale * ((*in >> 6));
               *cur++ = scale * ((*in >> 4) & 0x03);
               *cur++ = scale * ((*in >> 2) & 0x03);
               *cur++ = scale * ((*in) & 0x03);
            }
            if (k > 0)
               *cur++ = scale * ((*in >> 6));
            if (k > 1)
               *cur++ = scale * ((*in >> 4) & 0x03);
            if (k > 2)
               *cur++ = scale * ((*in >> 2) & 0x03);
         }
         else if (depth == 1)
         {
            for (k = x * img_n; k >= 8; k -= 8, ++in)
            {
               *cur++ = scale * ((*in >> 7));
               *cur++ = scale * ((*in >> 6) & 0x01);
               *cur++ = scale * ((*in >> 5) & 0x01);
               *cur++ = scale * ((*in >> 4) & 0x01);
               *cur++ = scale * ((*in >> 3) & 0x01);
               *cur++ = scale * ((*in >> 2) & 0x01);
               *cur++ = scale * ((*in >> 1) & 0x01);
               *cur++ = scale * ((*in) & 0x01);
            }
            if (k > 0)
               *cur++ = scale * ((*in >> 7));
            if (k > 1)
               *cur++ = scale * ((*in >> 6) & 0x01);
            if (k > 2)
               *cur++ = scale * ((*in >> 5) & 0x01);
            if (k > 3)
               *cur++ = scale * ((*in >> 4) & 0x01);
            if (k > 4)
               *cur++ = scale * ((*in >> 3) & 0x01);
            if (k > 5)
               *cur++ = scale * ((*in >> 2) & 0x01);
            if (k > 6)
               *cur++ = scale * ((*in >> 1) & 0x01);
         }
         if (img_n != out_n)
         {
            int q;
            // insert alpha = 255
            cur = a->out + stride * j;
            if (img_n == 1)
            {
               for (q = x - 1; q >= 0; --q)
               {
                  cur[q * 2 + 1] = 255;
                  cur[q * 2 + 0] = cur[q];
               }
            }
            else
            {
               STBI_ASSERT(img_n == 3);
               for (q = x - 1; q >= 0; --q)
               {
                  cur[q * 4 + 3] = 255;
                  cur[q * 4 + 2] = cur[q * 3 + 2];
                  cur[q * 4 + 1] = cur[q * 3 + 1];
                  cur[q * 4 + 0] = cur[q * 3 + 0];
               }
            }
         }
      }
   }
   else if (depth == 16)
   {
      // force the image data from big-endian to platform-native.
      // this is done in a separate pass due to the decoding relying
      // on the data being untouched, but could probably be done
      // per-line during decode if care is taken.
      stbi_uc *cur = a->out;
      stbi__uint16 *cur16 = (stbi__uint16 *)cur;

      for (i = 0; i < x * y * out_n; ++i, cur16++, cur += 2)
      {
         *cur16 = (cur[0] << 8) | cur[1];
      }
   }

   return 1;
}

static int stbi__create_png_image(stbi__png *a, stbi_uc *image_data, stbi__uint32 image_data_len, int out_n, int depth, int color, int interlaced)
{
   int bytes = (depth == 16 ? 2 : 1);
   int out_bytes = out_n * bytes;
   stbi_uc *final;
   int p;
   if (!interlaced)
      return stbi__create_png_image_raw(a, image_data, image_data_len, out_n, a->s->img_x, a->s->img_y, depth, color);

   // de-interlacing
   final = (stbi_uc *)stbi__malloc_mad3(a->s->img_x, a->s->img_y, out_bytes, 0);
   for (p = 0; p < 7; ++p)
   {
      int xorig[] = {0, 4, 0, 2, 0, 1, 0};
      int yorig[] = {0, 0, 4, 0, 2, 0, 1};
      int xspc[] = {8, 8, 4, 4, 2, 2, 1};
      int yspc[] = {8, 8, 8, 4, 4, 2, 2};
      int i, j, x, y;
      // pass1_x[4] = 0, pass1_x[5] = 1, pass1_x[12] = 1
      x = (a->s->img_x - xorig[p] + xspc[p] - 1) / xspc[p];
      y = (a->s->img_y - yorig[p] + yspc[p] - 1) / yspc[p];
      if (x && y)
      {
         stbi__uint32 img_len = ((((a->s->img_n * x * depth) + 7) >> 3) + 1) * y;
         if (!stbi__create_png_image_raw(a, image_data, image_data_len, out_n, x, y, depth, color))
         {
            STBI_FREE(final);
            return 0;
         }
         for (j = 0; j < y; ++j)
         {
            for (i = 0; i < x; ++i)
            {
               int out_y = j * yspc[p] + yorig[p];
               int out_x = i * xspc[p] + xorig[p];
               memcpy(final + out_y * a->s->img_x * out_bytes + out_x * out_bytes,
                      a->out + (j * x + i) * out_bytes, out_bytes);
            }
         }
         STBI_FREE(a->out);
         image_data += img_len;
         image_data_len -= img_len;
      }
   }
   a->out = final;

   return 1;
}

static int stbi__compute_transparency(stbi__png *z, stbi_uc tc[3], int out_n)
{
   stbi__context *s = z->s;
   stbi__uint32 i, pixel_count = s->img_x * s->img_y;
   stbi_uc *p = z->out;

   // compute color-based transparency, assuming we've
   // already got 255 as the alpha value in the output
   STBI_ASSERT(out_n == 2 || out_n == 4);

   if (out_n == 2)
   {
      for (i = 0; i < pixel_count; ++i)
      {
         p[1] = (p[0] == tc[0] ? 0 : 255);
         p += 2;
      }
   }
   else
   {
      for (i = 0; i < pixel_count; ++i)
      {
         if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
            p[3] = 0;
         p += 4;
      }
   }
   return 1;
}

static int stbi__compute_transparency16(stbi__png *z, stbi__uint16 tc[3], int out_n)
{
   stbi__context *s = z->s;
   stbi__uint32 i, pixel_count = s->img_x * s->img_y;
   stbi__uint16 *p = (stbi__uint16 *)z->out;

   // compute color-based transparency, assuming we've
   // already got 65535 as the alpha value in the output
   STBI_ASSERT(out_n == 2 || out_n == 4);

   if (out_n == 2)
   {
      for (i = 0; i < pixel_count; ++i)
      {
         p[1] = (p[0] == tc[0] ? 0 : 65535);
         p += 2;
      }
   }
   else
   {
      for (i = 0; i < pixel_count; ++i)
      {
         if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
            p[3] = 0;
         p += 4;
      }
   }
   return 1;
}

static int stbi__expand_png_palette(stbi__png *a, stbi_uc *palette, int len, int pal_img_n)
{
   stbi__uint32 i, pixel_count = a->s->img_x * a->s->img_y;
   stbi_uc *p, *temp_out, *orig = a->out;

   p = (stbi_uc *)stbi__malloc_mad2(pixel_count, pal_img_n, 0);
   if (p == NULL)
      return stbi__err("outofmem", "Out of memory");

   // between here and free(out) below, exitting would leak
   temp_out = p;

   if (pal_img_n == 3)
   {
      for (i = 0; i < pixel_count; ++i)
      {
         int n = orig[i] * 4;
         p[0] = palette[n];
         p[1] = palette[n + 1];
         p[2] = palette[n + 2];
         p += 3;
      }
   }
   else
   {
      for (i = 0; i < pixel_count; ++i)
      {
         int n = orig[i] * 4;
         p[0] = palette[n];
         p[1] = palette[n + 1];
         p[2] = palette[n + 2];
         p[3] = palette[n + 3];
         p += 4;
      }
   }
   STBI_FREE(a->out);
   a->out = temp_out;

   STBI_NOTUSED(len);

   return 1;
}

static int stbi__unpremultiply_on_load = 0;
static int stbi__de_iphone_flag = 0;

STBIDEF void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply)
{
   stbi__unpremultiply_on_load = flag_true_if_should_unpremultiply;
}

STBIDEF void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert)
{
   stbi__de_iphone_flag = flag_true_if_should_convert;
}

static void stbi__de_iphone(stbi__png *z)
{
   stbi__context *s = z->s;
   stbi__uint32 i, pixel_count = s->img_x * s->img_y;
   stbi_uc *p = z->out;

   if (s->img_out_n == 3)
   { // convert bgr to rgb
      for (i = 0; i < pixel_count; ++i)
      {
         stbi_uc t = p[0];
         p[0] = p[2];
         p[2] = t;
         p += 3;
      }
   }
   else
   {
      STBI_ASSERT(s->img_out_n == 4);
      if (stbi__unpremultiply_on_load)
      {
         // convert bgr to rgb and unpremultiply
         for (i = 0; i < pixel_count; ++i)
         {
            stbi_uc a = p[3];
            stbi_uc t = p[0];
            if (a)
            {
               stbi_uc half = a / 2;
               p[0] = (p[2] * 255 + half) / a;
               p[1] = (p[1] * 255 + half) / a;
               p[2] = (t * 255 + half) / a;
            }
            else
            {
               p[0] = p[2];
               p[2] = t;
            }
            p += 4;
         }
      }
      else
      {
         // convert bgr to rgb
         for (i = 0; i < pixel_count; ++i)
         {
            stbi_uc t = p[0];
            p[0] = p[2];
            p[2] = t;
            p += 4;
         }
      }
   }
}

#define STBI__PNG_TYPE(a, b, c, d) (((unsigned)(a) << 24) + ((unsigned)(b) << 16) + ((unsigned)(c) << 8) + (unsigned)(d))

static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp)
{
   stbi_uc palette[1024], pal_img_n = 0;
   stbi_uc has_trans = 0, tc[3] = {0};
   stbi__uint16 tc16[3];
   stbi__uint32 ioff = 0, idata_limit = 0, i, pal_len = 0;
   int first = 1, k, interlace = 0, color = 0, is_iphone = 0;
   stbi__context *s = z->s;

   z->expanded = NULL;
   z->idata = NULL;
   z->out = NULL;

   if (!stbi__check_png_header(s))
      return 0;

   if (scan == STBI__SCAN_type)
      return 1;

   for (;;)
   {
      stbi__pngchunk c = stbi__get_chunk_header(s);
      switch (c.type)
      {
      case STBI__PNG_TYPE('C', 'g', 'B', 'I'):
         is_iphone = 1;
         stbi__skip(s, c.length);
         break;
      case STBI__PNG_TYPE('I', 'H', 'D', 'R'):
      {
         int comp, filter;
         if (!first)
            return stbi__err("multiple IHDR", "Corrupt PNG");
         first = 0;
         if (c.length != 13)
            return stbi__err("bad IHDR len", "Corrupt PNG");
         s->img_x = stbi__get32be(s);
         if (s->img_x > (1 << 24))
            return stbi__err("too large", "Very large image (corrupt?)");
         s->img_y = stbi__get32be(s);
         if (s->img_y > (1 << 24))
            return stbi__err("too large", "Very large image (corrupt?)");
         z->depth = stbi__get8(s);
         if (z->depth != 1 && z->depth != 2 && z->depth != 4 && z->depth != 8 && z->depth != 16)
            return stbi__err("1/2/4/8/16-bit only", "PNG not supported: 1/2/4/8/16-bit only");
         color = stbi__get8(s);
         if (color > 6)
            return stbi__err("bad ctype", "Corrupt PNG");
         if (color == 3 && z->depth == 16)
            return stbi__err("bad ctype", "Corrupt PNG");
         if (color == 3)
            pal_img_n = 3;
         else if (color & 1)
            return stbi__err("bad ctype", "Corrupt PNG");
         comp = stbi__get8(s);
         if (comp)
            return stbi__err("bad comp method", "Corrupt PNG");
         filter = stbi__get8(s);
         if (filter)
            return stbi__err("bad filter method", "Corrupt PNG");
         interlace = stbi__get8(s);
         if (interlace > 1)
            return stbi__err("bad interlace method", "Corrupt PNG");
         if (!s->img_x || !s->img_y)
            return stbi__err("0-pixel image", "Corrupt PNG");
         if (!pal_img_n)
         {
            s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
            if ((1 << 30) / s->img_x / s->img_n < s->img_y)
               return stbi__err("too large", "Image too large to decode");
            if (scan == STBI__SCAN_header)
               return 1;
         }
         else
         {
            // if paletted, then pal_n is our final components, and
            // img_n is # components to decompress/filter.
            s->img_n = 1;
            if ((1 << 30) / s->img_x / 4 < s->img_y)
               return stbi__err("too large", "Corrupt PNG");
            // if SCAN_header, have to scan to see if we have a tRNS
         }
         break;
      }

      case STBI__PNG_TYPE('P', 'L', 'T', 'E'):
      {
         if (first)
            return stbi__err("first not IHDR", "Corrupt PNG");
         if (c.length > 256 * 3)
            return stbi__err("invalid PLTE", "Corrupt PNG");
         pal_len = c.length / 3;
         if (pal_len * 3 != c.length)
            return stbi__err("invalid PLTE", "Corrupt PNG");
         for (i = 0; i < pal_len; ++i)
         {
            palette[i * 4 + 0] = stbi__get8(s);
            palette[i * 4 + 1] = stbi__get8(s);
            palette[i * 4 + 2] = stbi__get8(s);
            palette[i * 4 + 3] = 255;
         }
         break;
      }

      case STBI__PNG_TYPE('t', 'R', 'N', 'S'):
      {
         if (first)
            return stbi__err("first not IHDR", "Corrupt PNG");
         if (z->idata)
            return stbi__err("tRNS after IDAT", "Corrupt PNG");
         if (pal_img_n)
         {
            if (scan == STBI__SCAN_header)
            {
               s->img_n = 4;
               return 1;
            }
            if (pal_len == 0)
               return stbi__err("tRNS before PLTE", "Corrupt PNG");
            if (c.length > pal_len)
               return stbi__err("bad tRNS len", "Corrupt PNG");
            pal_img_n = 4;
            for (i = 0; i < c.length; ++i)
               palette[i * 4 + 3] = stbi__get8(s);
         }
         else
         {
            if (!(s->img_n & 1))
               return stbi__err("tRNS with alpha", "Corrupt PNG");
            if (c.length != (stbi__uint32)s->img_n * 2)
               return stbi__err("bad tRNS len", "Corrupt PNG");
            has_trans = 1;
            if (z->depth == 16)
            {
               for (k = 0; k < s->img_n; ++k)
                  tc16[k] = (stbi__uint16)stbi__get16be(s); // copy the values as-is
            }
            else
            {
               for (k = 0; k < s->img_n; ++k)
                  tc[k] = (stbi_uc)(stbi__get16be(s) & 255) * stbi__depth_scale_table[z->depth]; // non 8-bit images will be larger
            }
         }
         break;
      }

      case STBI__PNG_TYPE('I', 'D', 'A', 'T'):
      {
         if (first)
            return stbi__err("first not IHDR", "Corrupt PNG");
         if (pal_img_n && !pal_len)
            return stbi__err("no PLTE", "Corrupt PNG");
         if (scan == STBI__SCAN_header)
         {
            s->img_n = pal_img_n;
            return 1;
         }
         if ((int)(ioff + c.length) < (int)ioff)
            return 0;
         if (ioff + c.length > idata_limit)
         {
            stbi__uint32 idata_limit_old = idata_limit;
            stbi_uc *p;
            if (idata_limit == 0)
               idata_limit = c.length > 4096 ? c.length : 4096;
            while (ioff + c.length > idata_limit)
               idata_limit *= 2;
            STBI_NOTUSED(idata_limit_old);
            p = (stbi_uc *)STBI_REALLOC_SIZED(z->idata, idata_limit_old, idata_limit);
            if (p == NULL)
               return stbi__err("outofmem", "Out of memory");
            z->idata = p;
         }
         if (!stbi__getn(s, z->idata + ioff, c.length))
            return stbi__err("outofdata", "Corrupt PNG");
         ioff += c.length;
         break;
      }

      case STBI__PNG_TYPE('I', 'E', 'N', 'D'):
      {
         stbi__uint32 raw_len, bpl;
         if (first)
            return stbi__err("first not IHDR", "Corrupt PNG");
         if (scan != STBI__SCAN_load)
            return 1;
         if (z->idata == NULL)
            return stbi__err("no IDAT", "Corrupt PNG");
         // initial guess for decoded data size to avoid unnecessary reallocs
         bpl = (s->img_x * z->depth + 7) / 8; // bytes per line, per component
         raw_len = bpl * s->img_y * s->img_n /* pixels */ + s->img_y /* filter mode per row */;
         z->expanded = (stbi_uc *)stbi_zlib_decode_malloc_guesssize_headerflag((char *)z->idata, ioff, raw_len, (int *)&raw_len, !is_iphone);
         if (z->expanded == NULL)
            return 0; // zlib should set error
         STBI_FREE(z->idata);
         z->idata = NULL;
         if ((req_comp == s->img_n + 1 && req_comp != 3 && !pal_img_n) || has_trans)
            s->img_out_n = s->img_n + 1;
         else
            s->img_out_n = s->img_n;
         if (!stbi__create_png_image(z, z->expanded, raw_len, s->img_out_n, z->depth, color, interlace))
            return 0;
         if (has_trans)
         {
            if (z->depth == 16)
            {
               if (!stbi__compute_transparency16(z, tc16, s->img_out_n))
                  return 0;
            }
            else
            {
               if (!stbi__compute_transparency(z, tc, s->img_out_n))
                  return 0;
            }
         }
         if (is_iphone && stbi__de_iphone_flag && s->img_out_n > 2)
            stbi__de_iphone(z);
         if (pal_img_n)
         {
            // pal_img_n == 3 or 4
            s->img_n = pal_img_n; // record the actual colors we had
            s->img_out_n = pal_img_n;
            if (req_comp >= 3)
               s->img_out_n = req_comp;
            if (!stbi__expand_png_palette(z, palette, pal_len, s->img_out_n))
               return 0;
         }
         else if (has_trans)
         {
            // non-paletted image with tRNS -> source image has (constant) alpha
            ++s->img_n;
         }
         STBI_FREE(z->expanded);
         z->expanded = NULL;
         // end of PNG chunk, read and skip CRC
         stbi__get32be(s);
         return 1;
      }

      default:
         // if critical, fail
         if (first)
            return stbi__err("first not IHDR", "Corrupt PNG");
         if ((c.type & (1 << 29)) == 0)
         {
#ifndef STBI_NO_FAILURE_STRINGS
            // not threadsafe
            static char invalid_chunk[] = "XXXX PNG chunk not known";
            invalid_chunk[0] = STBI__BYTECAST(c.type >> 24);
            invalid_chunk[1] = STBI__BYTECAST(c.type >> 16);
            invalid_chunk[2] = STBI__BYTECAST(c.type >> 8);
            invalid_chunk[3] = STBI__BYTECAST(c.type >> 0);
#endif
            return stbi__err(invalid_chunk, "PNG not supported: unknown PNG chunk type");
         }
         stbi__skip(s, c.length);
         break;
      }
      // end of PNG chunk, read and skip CRC
      stbi__get32be(s);
   }
}

static void *stbi__do_png(stbi__png *p, int *x, int *y, int *n, int req_comp, stbi__result_info *ri)
{
   void *result = NULL;
   if (req_comp < 0 || req_comp > 4)
      return stbi__errpuc("bad req_comp", "Internal error");
   if (stbi__parse_png_file(p, STBI__SCAN_load, req_comp))
   {
      if (p->depth < 8)
         ri->bits_per_channel = 8;
      else
         ri->bits_per_channel = p->depth;
      result = p->out;
      p->out = NULL;
      if (req_comp && req_comp != p->s->img_out_n)
      {
         if (ri->bits_per_channel == 8)
            result = stbi__convert_format((unsigned char *)result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
         else
            result = stbi__convert_format16((stbi__uint16 *)result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
         p->s->img_out_n = req_comp;
         if (result == NULL)
            return result;
      }
      *x = p->s->img_x;
      *y = p->s->img_y;
      if (n)
         *n = p->s->img_n;
   }
   STBI_FREE(p->out);
   p->out = NULL;
   STBI_FREE(p->expanded);
   p->expanded = NULL;
   STBI_FREE(p->idata);
   p->idata = NULL;

   return result;
}

static void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
{
   stbi__png p;
   p.s = s;
   return stbi__do_png(&p, x, y, comp, req_comp, ri);
}

static int stbi__png_test(stbi__context *s)
{
   int r;
   r = stbi__check_png_header(s);
   stbi__rewind(s);
   return r;
}

static int stbi__png_info_raw(stbi__png *p, int *x, int *y, int *comp)
{
   if (!stbi__parse_png_file(p, STBI__SCAN_header, 0))
   {
      stbi__rewind(p->s);
      return 0;
   }
   if (x)
      *x = p->s->img_x;
   if (y)
      *y = p->s->img_y;
   if (comp)
      *comp = p->s->img_n;
   return 1;
}

static int stbi__png_info(stbi__context *s, int *x, int *y, int *comp)
{
   stbi__png p;
   p.s = s;
   return stbi__png_info_raw(&p, x, y, comp);
}

static int stbi__png_is16(stbi__context *s)
{
   stbi__png p;
   p.s = s;
   if (!stbi__png_info_raw(&p, NULL, NULL, NULL))
      return 0;
   if (p.depth != 16)
   {
      stbi__rewind(p.s);
      return 0;
   }
   return 1;
}
#endif

// Microsoft/Windows BMP image

#ifndef STBI_NO_BMP
static int stbi__bmp_test_raw(stbi__context *s)
{
   int r;
   int sz;
   if (stbi__get8(s) != 'B')
      return 0;
   if (stbi__get8(s) != 'M')
      return 0;
   stbi__get32le(s); // discard filesize
   stbi__get16le(s); // discard reserved
   stbi__get16le(s); // discard reserved
   stbi__get32le(s); // discard data offset
   sz = stbi__get32le(s);
   r = (sz == 12 || sz == 40 || sz == 56 || sz == 108 || sz == 124);
   return r;
}

static int stbi__bmp_test(stbi__context *s)
{
   int r = stbi__bmp_test_raw(s);
   stbi__rewind(s);
   return r;
}

// returns 0..31 for the highest set bit
static int stbi__high_bit(unsigned int z)
{
   int n = 0;
   if (z == 0)
      return -1;
   if (z >= 0x10000)
   {
      n += 16;
      z >>= 16;
   }
   if (z >= 0x00100)
   {
      n += 8;
      z >>= 8;
   }
   if (z >= 0x00010)
   {
      n += 4;
      z >>= 4;
   }
   if (z >= 0x00004)
   {
      n += 2;
      z >>= 2;
   }
   if (z >= 0x00002)
   {
      n += 1; /* >>=  1;*/
   }
   return n;
}

static int stbi__bitcount(unsigned int a)
{
   a = (a & 0x55555555) + ((a >> 1) & 0x55555555); // max 2
   a = (a & 0x33333333) + ((a >> 2) & 0x33333333); // max 4
   a = (a + (a >> 4)) & 0x0f0f0f0f;                // max 8 per 4, now 8 bits
   a = (a + (a >> 8));                             // max 16 per 8 bits
   a = (a + (a >> 16));                            // max 32 per 8 bits
   return a & 0xff;
}

// extract an arbitrarily-aligned N-bit value (N=bits)
// from v, and then make it 8-bits long and fractionally
// extend it to full full range.
static int stbi__shiftsigned(unsigned int v, int shift, int bits)
{
   static unsigned int mul_table[9] = {
       0,
       0xff /*0b11111111*/,
       0x55 /*0b01010101*/,
       0x49 /*0b01001001*/,
       0x11 /*0b00010001*/,
       0x21 /*0b00100001*/,
       0x41 /*0b01000001*/,
       0x81 /*0b10000001*/,
       0x01 /*0b00000001*/,
   };
   static unsigned int shift_table[9] = {
       0,
       0,
       0,
       1,
       0,
       2,
       4,
       6,
       0,
   };
   if (shift < 0)
      v <<= -shift;
   else
      v >>= shift;
   STBI_ASSERT(v < 256);
   v >>= (8 - bits);
   STBI_ASSERT(bits >= 0 && bits <= 8);
   return (int)((unsigned)v * mul_table[bits]) >> shift_table[bits];
}

typedef struct
{
   int bpp, offset, hsz;
   unsigned int mr, mg, mb, ma, all_a;
   int extra_read;
} stbi__bmp_data;

static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
{
   int hsz;
   if (stbi__get8(s) != 'B' || stbi__get8(s) != 'M')
      return stbi__errpuc("not BMP", "Corrupt BMP");
   stbi__get32le(s); // discard filesize
   stbi__get16le(s); // discard reserved
   stbi__get16le(s); // discard reserved
   info->offset = stbi__get32le(s);
   info->hsz = hsz = stbi__get32le(s);
   info->mr = info->mg = info->mb = info->ma = 0;
   info->extra_read = 14;

   if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108 && hsz != 124)
      return stbi__errpuc("unknown BMP", "BMP type not supported: unknown");
   if (hsz == 12)
   {
      s->img_x = stbi__get16le(s);
      s->img_y = stbi__get16le(s);
   }
   else
   {
      s->img_x = stbi__get32le(s);
      s->img_y = stbi__get32le(s);
   }
   if (stbi__get16le(s) != 1)
      return stbi__errpuc("bad BMP", "bad BMP");
   info->bpp = stbi__get16le(s);
   if (hsz != 12)
   {
      int compress = stbi__get32le(s);
      if (compress == 1 || compress == 2)
         return stbi__errpuc("BMP RLE", "BMP type not supported: RLE");
      stbi__get32le(s); // discard sizeof
      stbi__get32le(s); // discard hres
      stbi__get32le(s); // discard vres
      stbi__get32le(s); // discard colorsused
      stbi__get32le(s); // discard max important
      if (hsz == 40 || hsz == 56)
      {
         if (hsz == 56)
         {
            stbi__get32le(s);
            stbi__get32le(s);
            stbi__get32le(s);
            stbi__get32le(s);
         }
         if (info->bpp == 16 || info->bpp == 32)
         {
            if (compress == 0)
            {
               if (info->bpp == 32)
               {
                  info->mr = 0xffu << 16;
                  info->mg = 0xffu << 8;
                  info->mb = 0xffu << 0;
                  info->ma = 0xffu << 24;
                  info->all_a = 0; // if all_a is 0 at end, then we loaded alpha channel but it was all 0
               }
               else
               {
                  info->mr = 31u << 10;
                  info->mg = 31u << 5;
                  info->mb = 31u << 0;
               }
            }
            else if (compress == 3)
            {
               info->mr = stbi__get32le(s);
               info->mg = stbi__get32le(s);
               info->mb = stbi__get32le(s);
               info->extra_read += 12;
               // not documented, but generated by photoshop and handled by mspaint
               if (info->mr == info->mg && info->mg == info->mb)
               {
                  // ?!?!?
                  return stbi__errpuc("bad BMP", "bad BMP");
               }
            }
            else
               return stbi__errpuc("bad BMP", "bad BMP");
         }
      }
      else
      {
         int i;
         if (hsz != 108 && hsz != 124)
            return stbi__errpuc("bad BMP", "bad BMP");
         info->mr = stbi__get32le(s);
         info->mg = stbi__get32le(s);
         info->mb = stbi__get32le(s);
         info->ma = stbi__get32le(s);
         stbi__get32le(s); // discard color space
         for (i = 0; i < 12; ++i)
            stbi__get32le(s); // discard color space parameters
         if (hsz == 124)
         {
            stbi__get32le(s); // discard rendering intent
            stbi__get32le(s); // discard offset of profile data
            stbi__get32le(s); // discard size of profile data
            stbi__get32le(s); // discard reserved
         }
      }
   }
   return (void *)1;
}

static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
{
   stbi_uc *out;
   unsigned int mr = 0, mg = 0, mb = 0, ma = 0, all_a;
   stbi_uc pal[256][4];
   int psize = 0, i, j, width;
   int flip_vertically, pad, target;
   stbi__bmp_data info;
   STBI_NOTUSED(ri);

   info.all_a = 255;
   if (stbi__bmp_parse_header(s, &info) == NULL)
      return NULL; // error code already set

   flip_vertically = ((int)s->img_y) > 0;
   s->img_y = abs((int)s->img_y);

   mr = info.mr;
   mg = info.mg;
   mb = info.mb;
   ma = info.ma;
   all_a = info.all_a;

   if (info.hsz == 12)
   {
      if (info.bpp < 24)
         psize = (info.offset - info.extra_read - 24) / 3;
   }
   else
   {
      if (info.bpp < 16)
         psize = (info.offset - info.extra_read - info.hsz) >> 2;
   }
   if (psize == 0)
   {
      STBI_ASSERT(info.offset == (s->img_buffer - s->buffer_start));
   }

   if (info.bpp == 24 && ma == 0xff000000)
      s->img_n = 3;
   else
      s->img_n = ma ? 4 : 3;
   if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
      target = req_comp;
   else
      target = s->img_n; // if they want monochrome, we'll post-convert

   // sanity-check size
   if (!stbi__mad3sizes_valid(target, s->img_x, s->img_y, 0))
      return stbi__errpuc("too large", "Corrupt BMP");

   out = (stbi_uc *)stbi__malloc_mad3(target, s->img_x, s->img_y, 0);
   if (!out)
      return stbi__errpuc("outofmem", "Out of memory");
   if (info.bpp < 16)
   {
      int z = 0;
      if (psize == 0 || psize > 256)
      {
         STBI_FREE(out);
         return stbi__errpuc("invalid", "Corrupt BMP");
      }
      for (i = 0; i < psize; ++i)
      {
         pal[i][2] = stbi__get8(s);
         pal[i][1] = stbi__get8(s);
         pal[i][0] = stbi__get8(s);
         if (info.hsz != 12)
            stbi__get8(s);
         pal[i][3] = 255;
      }
      stbi__skip(s, info.offset - info.extra_read - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
      if (info.bpp == 1)
         width = (s->img_x + 7) >> 3;
      else if (info.bpp == 4)
         width = (s->img_x + 1) >> 1;
      else if (info.bpp == 8)
         width = s->img_x;
      else
      {
         STBI_FREE(out);
         return stbi__errpuc("bad bpp", "Corrupt BMP");
      }
      pad = (-width) & 3;
      if (info.bpp == 1)
      {
         for (j = 0; j < (int)s->img_y; ++j)
         {
            int bit_offset = 7, v = stbi__get8(s);
            for (i = 0; i < (int)s->img_x; ++i)
            {
               int color = (v >> bit_offset) & 0x1;
               out[z++] = pal[color][0];
               out[z++] = pal[color][1];
               out[z++] = pal[color][2];
               if (target == 4)
                  out[z++] = 255;
               if (i + 1 == (int)s->img_x)
                  break;
               if ((--bit_offset) < 0)
               {
                  bit_offset = 7;
                  v = stbi__get8(s);
               }
            }
            stbi__skip(s, pad);
         }
      }
      else
      {
         for (j = 0; j < (int)s->img_y; ++j)
         {
            for (i = 0; i < (int)s->img_x; i += 2)
            {
               int v = stbi__get8(s), v2 = 0;
               if (info.bpp == 4)
               {
                  v2 = v & 15;
                  v >>= 4;
               }
               out[z++] = pal[v][0];
               out[z++] = pal[v][1];
               out[z++] = pal[v][2];
               if (target == 4)
                  out[z++] = 255;
               if (i + 1 == (int)s->img_x)
                  break;
               v = (info.bpp == 8) ? stbi__get8(s) : v2;
               out[z++] = pal[v][0];
               out[z++] = pal[v][1];
               out[z++] = pal[v][2];
               if (target == 4)
                  out[z++] = 255;
            }
            stbi__skip(s, pad);
         }
      }
   }
   else
   {
      int rshift = 0, gshift = 0, bshift = 0, ashift = 0, rcount = 0, gcount = 0, bcount = 0, acount = 0;
      int z = 0;
      int easy = 0;
      stbi__skip(s, info.offset - info.extra_read - info.hsz);
      if (info.bpp == 24)
         width = 3 * s->img_x;
      else if (info.bpp == 16)
         width = 2 * s->img_x;
      else /* bpp = 32 and pad = 0 */
         width = 0;
      pad = (-width) & 3;
      if (info.bpp == 24)
      {
         easy = 1;
      }
      else if (info.bpp == 32)
      {
         if (mb == 0xff && mg == 0xff00 && mr == 0x00ff0000 && ma == 0xff000000)
            easy = 2;
      }
      if (!easy)
      {
         if (!mr || !mg || !mb)
         {
            STBI_FREE(out);
            return stbi__errpuc("bad masks", "Corrupt BMP");
         }
         // right shift amt to put high bit in position #7
         rshift = stbi__high_bit(mr) - 7;
         rcount = stbi__bitcount(mr);
         gshift = stbi__high_bit(mg) - 7;
         gcount = stbi__bitcount(mg);
         bshift = stbi__high_bit(mb) - 7;
         bcount = stbi__bitcount(mb);
         ashift = stbi__high_bit(ma) - 7;
         acount = stbi__bitcount(ma);
      }
      for (j = 0; j < (int)s->img_y; ++j)
      {
         if (easy)
         {
            for (i = 0; i < (int)s->img_x; ++i)
            {
               unsigned char a;
               out[z + 2] = stbi__get8(s);
               out[z + 1] = stbi__get8(s);
               out[z + 0] = stbi__get8(s);
               z += 3;
               a = (easy == 2 ? stbi__get8(s) : 255);
               all_a |= a;
               if (target == 4)
                  out[z++] = a;
            }
         }
         else
         {
            int bpp = info.bpp;
            for (i = 0; i < (int)s->img_x; ++i)
            {
               stbi__uint32 v = (bpp == 16 ? (stbi__uint32)stbi__get16le(s) : stbi__get32le(s));
               unsigned int a;
               out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mr, rshift, rcount));
               out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mg, gshift, gcount));
               out[z++] = STBI__BYTECAST(stbi__shiftsigned(v & mb, bshift, bcount));
               a = (ma ? stbi__shiftsigned(v & ma, ashift, acount) : 255);
               all_a |= a;
               if (target == 4)
                  out[z++] = STBI__BYTECAST(a);
            }
         }
         stbi__skip(s, pad);
      }
   }

   // if alpha channel is all 0s, replace with all 255s
   if (target == 4 && all_a == 0)
      for (i = 4 * s->img_x * s->img_y - 1; i >= 0; i -= 4)
         out[i] = 255;

   if (flip_vertically)
   {
      stbi_uc t;
      for (j = 0; j<(int)s->img_y>> 1; ++j)
      {
         stbi_uc *p1 = out + j * s->img_x * target;
         stbi_uc *p2 = out + (s->img_y - 1 - j) * s->img_x * target;
         for (i = 0; i < (int)s->img_x * target; ++i)
         {
            t = p1[i];
            p1[i] = p2[i];
            p2[i] = t;
         }
      }
   }

   if (req_comp && req_comp != target)
   {
      out = stbi__convert_format(out, target, req_comp, s->img_x, s->img_y);
      if (out == NULL)
         return out; // stbi__convert_format frees input on failure
   }

   *x = s->img_x;
   *y = s->img_y;
   if (comp)
      *comp = s->img_n;
   return out;
}
#endif

// Targa Truevision - TGA
// by Jonathan Dummer
#ifndef STBI_NO_TGA
// returns STBI_rgb or whatever, 0 on error
static int stbi__tga_get_comp(int bits_per_pixel, int is_grey, int *is_rgb16)
{
   // only RGB or RGBA (incl. 16bit) or grey allowed
   if (is_rgb16)
      *is_rgb16 = 0;
   switch (bits_per_pixel)
   {
   case 8:
      return STBI_grey;
   case 16:
      if (is_grey)
         return STBI_grey_alpha;
      // fallthrough
   case 15:
      if (is_rgb16)
         *is_rgb16 = 1;
      return STBI_rgb;
   case 24: // fallthrough
   case 32:
      return bits_per_pixel / 8;
   default:
      return 0;
   }
}

static int stbi__tga_info(stbi__context *s, int *x, int *y, int *comp)
{
   int tga_w, tga_h, tga_comp, tga_image_type, tga_bits_per_pixel, tga_colormap_bpp;
   int sz, tga_colormap_type;
   stbi__get8(s);                     // discard Offset
   tga_colormap_type = stbi__get8(s); // colormap type
   if (tga_colormap_type > 1)
   {
      stbi__rewind(s);
      return 0; // only RGB or indexed allowed
   }
   tga_image_type = stbi__get8(s); // image type
   if (tga_colormap_type == 1)
   { // colormapped (paletted) image
      if (tga_image_type != 1 && tga_image_type != 9)
      {
         stbi__rewind(s);
         return 0;
      }
      stbi__skip(s, 4);   // skip index of first colormap entry and number of entries
      sz = stbi__get8(s); //   check bits per palette color entry
      if ((sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32))
      {
         stbi__rewind(s);
         return 0;
      }
      stbi__skip(s, 4); // skip image x and y origin
      tga_colormap_bpp = sz;
   }
   else
   { // "normal" image w/o colormap - only RGB or grey allowed, +/- RLE
      if ((tga_image_type != 2) && (tga_image_type != 3) && (tga_image_type != 10) && (tga_image_type != 11))
      {
         stbi__rewind(s);
         return 0; // only RGB or grey allowed, +/- RLE
      }
      stbi__skip(s, 9); // skip colormap specification and image x/y origin
      tga_colormap_bpp = 0;
   }
   tga_w = stbi__get16le(s);
   if (tga_w < 1)
   {
      stbi__rewind(s);
      return 0; // test width
   }
   tga_h = stbi__get16le(s);
   if (tga_h < 1)
   {
      stbi__rewind(s);
      return 0; // test height
   }
   tga_bits_per_pixel = stbi__get8(s); // bits per pixel
   stbi__get8(s);                      // ignore alpha bits
   if (tga_colormap_bpp != 0)
   {
      if ((tga_bits_per_pixel != 8) && (tga_bits_per_pixel != 16))
      {
         // when using a colormap, tga_bits_per_pixel is the size of the indexes
         // I don't think anything but 8 or 16bit indexes makes sense
         stbi__rewind(s);
         return 0;
      }
      tga_comp = stbi__tga_get_comp(tga_colormap_bpp, 0, NULL);
   }
   else
   {
      tga_comp = stbi__tga_get_comp(tga_bits_per_pixel, (tga_image_type == 3) || (tga_image_type == 11), NULL);
   }
   if (!tga_comp)
   {
      stbi__rewind(s);
      return 0;
   }
   if (x)
      *x = tga_w;
   if (y)
      *y = tga_h;
   if (comp)
      *comp = tga_comp;
   return 1; // seems to have passed everything
}

static int stbi__tga_test(stbi__context *s)
{
   int res = 0;
   int sz, tga_color_type;
   stbi__get8(s);                  //   discard Offset
   tga_color_type = stbi__get8(s); //   color type
   if (tga_color_type > 1)
      goto errorEnd;   //   only RGB or indexed allowed
   sz = stbi__get8(s); //   image type
   if (tga_color_type == 1)
   { // colormapped (paletted) image
      if (sz != 1 && sz != 9)
         goto errorEnd;   // colortype 1 demands image type 1 or 9
      stbi__skip(s, 4);   // skip index of first colormap entry and number of entries
      sz = stbi__get8(s); //   check bits per palette color entry
      if ((sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32))
         goto errorEnd;
      stbi__skip(s, 4); // skip image x and y origin
   }
   else
   { // "normal" image w/o colormap
      if ((sz != 2) && (sz != 3) && (sz != 10) && (sz != 11))
         goto errorEnd; // only RGB or grey allowed, +/- RLE
      stbi__skip(s, 9); // skip colormap specification and image x/y origin
   }
   if (stbi__get16le(s) < 1)
      goto errorEnd; //   test width
   if (stbi__get16le(s) < 1)
      goto errorEnd;   //   test height
   sz = stbi__get8(s); //   bits per pixel
   if ((tga_color_type == 1) && (sz != 8) && (sz != 16))
      goto errorEnd; // for colormapped images, bpp is size of an index
   if ((sz != 8) && (sz != 15) && (sz != 16) && (sz != 24) && (sz != 32))
      goto errorEnd;

   res = 1; // if we got this far, everything's good and we can return 1 instead of 0

errorEnd:
   stbi__rewind(s);
   return res;
}

// read 16bit value and convert to 24bit RGB
static void stbi__tga_read_rgb16(stbi__context *s, stbi_uc *out)
{
   stbi__uint16 px = (stbi__uint16)stbi__get16le(s);
   stbi__uint16 fiveBitMask = 31;
   // we have 3 channels with 5bits each
   int r = (px >> 10) & fiveBitMask;
   int g = (px >> 5) & fiveBitMask;
   int b = px & fiveBitMask;
   // Note that this saves the data in RGB(A) order, so it doesn't need to be swapped later
   out[0] = (stbi_uc)((r * 255) / 31);
   out[1] = (stbi_uc)((g * 255) / 31);
   out[2] = (stbi_uc)((b * 255) / 31);

   // some people claim that the most significant bit might be used for alpha
   // (possibly if an alpha-bit is set in the "image descriptor byte")
   // but that only made 16bit test images completely translucent..
   // so let's treat all 15 and 16bit TGAs as RGB with no alpha.
}

static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
{
   //   read in the TGA header stuff
   int tga_offset = stbi__get8(s);
   int tga_indexed = stbi__get8(s);
   int tga_image_type = stbi__get8(s);
   int tga_is_RLE = 0;
   int tga_palette_start = stbi__get16le(s);
   int tga_palette_len = stbi__get16le(s);
   int tga_palette_bits = stbi__get8(s);
   int tga_x_origin = stbi__get16le(s);
   int tga_y_origin = stbi__get16le(s);
   int tga_width = stbi__get16le(s);
   int tga_height = stbi__get16le(s);
   int tga_bits_per_pixel = stbi__get8(s);
   int tga_comp, tga_rgb16 = 0;
   int tga_inverted = stbi__get8(s);
   // int tga_alpha_bits = tga_inverted & 15; // the 4 lowest bits - unused (useless?)
   //   image data
   unsigned char *tga_data;
   unsigned char *tga_palette = NULL;
   int i, j;
   unsigned char raw_data[4] = {0};
   int RLE_count = 0;
   int RLE_repeating = 0;
   int read_next_pixel = 1;
   STBI_NOTUSED(ri);
   STBI_NOTUSED(tga_x_origin); // @TODO
   STBI_NOTUSED(tga_y_origin); // @TODO

   //   do a tiny bit of precessing
   if (tga_image_type >= 8)
   {
      tga_image_type -= 8;
      tga_is_RLE = 1;
   }
   tga_inverted = 1 - ((tga_inverted >> 5) & 1);

   //   If I'm paletted, then I'll use the number of bits from the palette
   if (tga_indexed)
      tga_comp = stbi__tga_get_comp(tga_palette_bits, 0, &tga_rgb16);
   else
      tga_comp = stbi__tga_get_comp(tga_bits_per_pixel, (tga_image_type == 3), &tga_rgb16);

   if (!tga_comp) // shouldn't really happen, stbi__tga_test() should have ensured basic consistency
      return stbi__errpuc("bad format", "Can't find out TGA pixelformat");

   //   tga info
   *x = tga_width;
   *y = tga_height;
   if (comp)
      *comp = tga_comp;

   if (!stbi__mad3sizes_valid(tga_width, tga_height, tga_comp, 0))
      return stbi__errpuc("too large", "Corrupt TGA");

   tga_data = (unsigned char *)stbi__malloc_mad3(tga_width, tga_height, tga_comp, 0);
   if (!tga_data)
      return stbi__errpuc("outofmem", "Out of memory");

   // skip to the data's starting position (offset usually = 0)
   stbi__skip(s, tga_offset);

   if (!tga_indexed && !tga_is_RLE && !tga_rgb16)
   {
      for (i = 0; i < tga_height; ++i)
      {
         int row = tga_inverted ? tga_height - i - 1 : i;
         stbi_uc *tga_row = tga_data + row * tga_width * tga_comp;
         stbi__getn(s, tga_row, tga_width * tga_comp);
      }
   }
   else
   {
      //   do I need to load a palette?
      if (tga_indexed)
      {
         //   any data to skip? (offset usually = 0)
         stbi__skip(s, tga_palette_start);
         //   load the palette
         tga_palette = (unsigned char *)stbi__malloc_mad2(tga_palette_len, tga_comp, 0);
         if (!tga_palette)
         {
            STBI_FREE(tga_data);
            return stbi__errpuc("outofmem", "Out of memory");
         }
         if (tga_rgb16)
         {
            stbi_uc *pal_entry = tga_palette;
            STBI_ASSERT(tga_comp == STBI_rgb);
            for (i = 0; i < tga_palette_len; ++i)
            {
               stbi__tga_read_rgb16(s, pal_entry);
               pal_entry += tga_comp;
            }
         }
         else if (!stbi__getn(s, tga_palette, tga_palette_len * tga_comp))
         {
            STBI_FREE(tga_data);
            STBI_FREE(tga_palette);
            return stbi__errpuc("bad palette", "Corrupt TGA");
         }
      }
      //   load the data
      for (i = 0; i < tga_width * tga_height; ++i)
      {
         //   if I'm in RLE mode, do I need to get a RLE stbi__pngchunk?
         if (tga_is_RLE)
         {
            if (RLE_count == 0)
            {
               //   yep, get the next byte as a RLE command
               int RLE_cmd = stbi__get8(s);
               RLE_count = 1 + (RLE_cmd & 127);
               RLE_repeating = RLE_cmd >> 7;
               read_next_pixel = 1;
            }
            else if (!RLE_repeating)
            {
               read_next_pixel = 1;
            }
         }
         else
         {
            read_next_pixel = 1;
         }
         //   OK, if I need to read a pixel, do it now
         if (read_next_pixel)
         {
            //   load however much data we did have
            if (tga_indexed)
            {
               // read in index, then perform the lookup
               int pal_idx = (tga_bits_per_pixel == 8) ? stbi__get8(s) : stbi__get16le(s);
               if (pal_idx >= tga_palette_len)
               {
                  // invalid index
                  pal_idx = 0;
               }
               pal_idx *= tga_comp;
               for (j = 0; j < tga_comp; ++j)
               {
                  raw_data[j] = tga_palette[pal_idx + j];
               }
            }
            else if (tga_rgb16)
            {
               STBI_ASSERT(tga_comp == STBI_rgb);
               stbi__tga_read_rgb16(s, raw_data);
            }
            else
            {
               //   read in the data raw
               for (j = 0; j < tga_comp; ++j)
               {
                  raw_data[j] = stbi__get8(s);
               }
            }
            //   clear the reading flag for the next pixel
            read_next_pixel = 0;
         } // end of reading a pixel

         // copy data
         for (j = 0; j < tga_comp; ++j)
            tga_data[i * tga_comp + j] = raw_data[j];

         //   in case we're in RLE mode, keep counting down
         --RLE_count;
      }
      //   do I need to invert the image?
      if (tga_inverted)
      {
         for (j = 0; j * 2 < tga_height; ++j)
         {
            int index1 = j * tga_width * tga_comp;
            int index2 = (tga_height - 1 - j) * tga_width * tga_comp;
            for (i = tga_width * tga_comp; i > 0; --i)
            {
               unsigned char temp = tga_data[index1];
               tga_data[index1] = tga_data[index2];
               tga_data[index2] = temp;
               ++index1;
               ++index2;
            }
         }
      }
      //   clear my palette, if I had one
      if (tga_palette != NULL)
      {
         STBI_FREE(tga_palette);
      }
   }

   // swap RGB - if the source data was RGB16, it already is in the right order
   if (tga_comp >= 3 && !tga_rgb16)
   {
      unsigned char *tga_pixel = tga_data;
      for (i = 0; i < tga_width * tga_height; ++i)
      {
         unsigned char temp = tga_pixel[0];
         tga_pixel[0] = tga_pixel[2];
         tga_pixel[2] = temp;
         tga_pixel += tga_comp;
      }
   }

   // convert to target component count
   if (req_comp && req_comp != tga_comp)
      tga_data = stbi__convert_format(tga_data, tga_comp, req_comp, tga_width, tga_height);

   //   the things I do to get rid of an error message, and yet keep
   //   Microsoft's C compilers happy... [8^(
   tga_palette_start = tga_palette_len = tga_palette_bits =
       tga_x_origin = tga_y_origin = 0;
   STBI_NOTUSED(tga_palette_start);
   //   OK, done
   return tga_data;
}
#endif

// *************************************************************************************************
// Photoshop PSD loader -- PD by Thatcher Ulrich, integration by Nicolas Schulz, tweaked by STB

#ifndef STBI_NO_PSD
static int stbi__psd_test(stbi__context *s)
{
   int r = (stbi__get32be(s) == 0x38425053);
   stbi__rewind(s);
   return r;
}

static int stbi__psd_decode_rle(stbi__context *s, stbi_uc *p, int pixelCount)
{
   int count, nleft, len;

   count = 0;
   while ((nleft = pixelCount - count) > 0)
   {
      len = stbi__get8(s);
      if (len == 128)
      {
         // No-op.
      }
      else if (len < 128)
      {
         // Copy next len+1 bytes literally.
         len++;
         if (len > nleft)
            return 0; // corrupt data
         count += len;
         while (len)
         {
            *p = stbi__get8(s);
            p += 4;
            len--;
         }
      }
      else if (len > 128)
      {
         stbi_uc val;
         // Next -len+1 bytes in the dest are replicated from next source byte.
         // (Interpret len as a negative 8-bit int.)
         len = 257 - len;
         if (len > nleft)
            return 0; // corrupt data
         val = stbi__get8(s);
         count += len;
         while (len)
         {
            *p = val;
            p += 4;
            len--;
         }
      }
   }

   return 1;
}

static void *stbi__psd_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
{
   int pixelCount;
   int channelCount, compression;
   int channel, i;
   int bitdepth;
   int w, h;
   stbi_uc *out;
   STBI_NOTUSED(ri);

   // Check identifier
   if (stbi__get32be(s) != 0x38425053) // "8BPS"
      return stbi__errpuc("not PSD", "Corrupt PSD image");

   // Check file type version.
   if (stbi__get16be(s) != 1)
      return stbi__errpuc("wrong version", "Unsupported version of PSD image");

   // Skip 6 reserved bytes.
   stbi__skip(s, 6);

   // Read the number of channels (R, G, B, A, etc).
   channelCount = stbi__get16be(s);
   if (channelCount < 0 || channelCount > 16)
      return stbi__errpuc("wrong channel count", "Unsupported number of channels in PSD image");

   // Read the rows and columns of the image.
   h = stbi__get32be(s);
   w = stbi__get32be(s);

   // Make sure the depth is 8 bits.
   bitdepth = stbi__get16be(s);
   if (bitdepth != 8 && bitdepth != 16)
      return stbi__errpuc("unsupported bit depth", "PSD bit depth is not 8 or 16 bit");

   // Make sure the color mode is RGB.
   // Valid options are:
   //   0: Bitmap
   //   1: Grayscale
   //   2: Indexed color
   //   3: RGB color
   //   4: CMYK color
   //   7: Multichannel
   //   8: Duotone
   //   9: Lab color
   if (stbi__get16be(s) != 3)
      return stbi__errpuc("wrong color format", "PSD is not in RGB color format");

   // Skip the Mode Data.  (It's the palette for indexed color; other info for other modes.)
   stbi__skip(s, stbi__get32be(s));

   // Skip the image resources.  (resolution, pen tool paths, etc)
   stbi__skip(s, stbi__get32be(s));

   // Skip the reserved data.
   stbi__skip(s, stbi__get32be(s));

   // Find out if the data is compressed.
   // Known values:
   //   0: no compression
   //   1: RLE compressed
   compression = stbi__get16be(s);
   if (compression > 1)
      return stbi__errpuc("bad compression", "PSD has an unknown compression format");

   // Check size
   if (!stbi__mad3sizes_valid(4, w, h, 0))
      return stbi__errpuc("too large", "Corrupt PSD");

   // Create the destination image.

   if (!compression && bitdepth == 16 && bpc == 16)
   {
      out = (stbi_uc *)stbi__malloc_mad3(8, w, h, 0);
      ri->bits_per_channel = 16;
   }
   else
      out = (stbi_uc *)stbi__malloc(4 * w * h);

   if (!out)
      return stbi__errpuc("outofmem", "Out of memory");
   pixelCount = w * h;

   // Initialize the data to zero.
   //memset( out, 0, pixelCount * 4 );

   // Finally, the image data.
   if (compression)
   {
      // RLE as used by .PSD and .TIFF
      // Loop until you get the number of unpacked bytes you are expecting:
      //     Read the next source byte into n.
      //     If n is between 0 and 127 inclusive, copy the next n+1 bytes literally.
      //     Else if n is between -127 and -1 inclusive, copy the next byte -n+1 times.
      //     Else if n is 128, noop.
      // Endloop

      // The RLE-compressed data is preceded by a 2-byte data count for each row in the data,
      // which we're going to just skip.
      stbi__skip(s, h * channelCount * 2);

      // Read the RLE data by channel.
      for (channel = 0; channel < 4; channel++)
      {
         stbi_uc *p;

         p = out + channel;
         if (channel >= channelCount)
         {
            // Fill this channel with default data.
            for (i = 0; i < pixelCount; i++, p += 4)
               *p = (channel == 3 ? 255 : 0);
         }
         else
         {
            // Read the RLE data.
            if (!stbi__psd_decode_rle(s, p, pixelCount))
            {
               STBI_FREE(out);
               return stbi__errpuc("corrupt", "bad RLE data");
            }
         }
      }
   }
   else
   {
      // We're at the raw image data.  It's each channel in order (Red, Green, Blue, Alpha, ...)
      // where each channel consists of an 8-bit (or 16-bit) value for each pixel in the image.

      // Read the data by channel.
      for (channel = 0; channel < 4; channel++)
      {
         if (channel >= channelCount)
         {
            // Fill this channel with default data.
            if (bitdepth == 16 && bpc == 16)
            {
               stbi__uint16 *q = ((stbi__uint16 *)out) + channel;
               stbi__uint16 val = channel == 3 ? 65535 : 0;
               for (i = 0; i < pixelCount; i++, q += 4)
                  *q = val;
            }
            else
            {
               stbi_uc *p = out + channel;
               stbi_uc val = channel == 3 ? 255 : 0;
               for (i = 0; i < pixelCount; i++, p += 4)
                  *p = val;
            }
         }
         else
         {
            if (ri->bits_per_channel == 16)
            { // output bpc
               stbi__uint16 *q = ((stbi__uint16 *)out) + channel;
               for (i = 0; i < pixelCount; i++, q += 4)
                  *q = (stbi__uint16)stbi__get16be(s);
            }
            else
            {
               stbi_uc *p = out + channel;
               if (bitdepth == 16)
               { // input bpc
                  for (i = 0; i < pixelCount; i++, p += 4)
                     *p = (stbi_uc)(stbi__get16be(s) >> 8);
               }
               else
               {
                  for (i = 0; i < pixelCount; i++, p += 4)
                     *p = stbi__get8(s);
               }
            }
         }
      }
   }

   // remove weird white matte from PSD
   if (channelCount >= 4)
   {
      if (ri->bits_per_channel == 16)
      {
         for (i = 0; i < w * h; ++i)
         {
            stbi__uint16 *pixel = (stbi__uint16 *)out + 4 * i;
            if (pixel[3] != 0 && pixel[3] != 65535)
            {
               float a = pixel[3] / 65535.0f;
               float ra = 1.0f / a;
               float inv_a = 65535.0f * (1 - ra);
               pixel[0] = (stbi__uint16)(pixel[0] * ra + inv_a);
               pixel[1] = (stbi__uint16)(pixel[1] * ra + inv_a);
               pixel[2] = (stbi__uint16)(pixel[2] * ra + inv_a);
            }
         }
      }
      else
      {
         for (i = 0; i < w * h; ++i)
         {
            unsigned char *pixel = out + 4 * i;
            if (pixel[3] != 0 && pixel[3] != 255)
            {
               float a = pixel[3] / 255.0f;
               float ra = 1.0f / a;
               float inv_a = 255.0f * (1 - ra);
               pixel[0] = (unsigned char)(pixel[0] * ra + inv_a);
               pixel[1] = (unsigned char)(pixel[1] * ra + inv_a);
               pixel[2] = (unsigned char)(pixel[2] * ra + inv_a);
            }
         }
      }
   }

   // convert to desired output format
   if (req_comp && req_comp != 4)
   {
      if (ri->bits_per_channel == 16)
         out = (stbi_uc *)stbi__convert_format16((stbi__uint16 *)out, 4, req_comp, w, h);
      else
         out = stbi__convert_format(out, 4, req_comp, w, h);
      if (out == NULL)
         return out; // stbi__convert_format frees input on failure
   }

   if (comp)
      *comp = 4;
   *y = h;
   *x = w;

   return out;
}
#endif

// *************************************************************************************************
// Softimage PIC loader
// by Tom Seddon
//
// See http://softimage.wiki.softimage.com/index.php/INFO:_PIC_file_format
// See http://ozviz.wasp.uwa.edu.au/~pbourke/dataformats/softimagepic/

#ifndef STBI_NO_PIC
static int stbi__pic_is4(stbi__context *s, const char *str)
{
   int i;
   for (i = 0; i < 4; ++i)
      if (stbi__get8(s) != (stbi_uc)str[i])
         return 0;

   return 1;
}

static int stbi__pic_test_core(stbi__context *s)
{
   int i;

   if (!stbi__pic_is4(s, "\x53\x80\xF6\x34"))
      return 0;

   for (i = 0; i < 84; ++i)
      stbi__get8(s);

   if (!stbi__pic_is4(s, "PICT"))
      return 0;

   return 1;
}

typedef struct
{
   stbi_uc size, type, channel;
} stbi__pic_packet;

static stbi_uc *stbi__readval(stbi__context *s, int channel, stbi_uc *dest)
{
   int mask = 0x80, i;

   for (i = 0; i < 4; ++i, mask >>= 1)
   {
      if (channel & mask)
      {
         if (stbi__at_eof(s))
            return stbi__errpuc("bad file", "PIC file too short");
         dest[i] = stbi__get8(s);
      }
   }

   return dest;
}

static void stbi__copyval(int channel, stbi_uc *dest, const stbi_uc *src)
{
   int mask = 0x80, i;

   for (i = 0; i < 4; ++i, mask >>= 1)
      if (channel & mask)
         dest[i] = src[i];
}

static stbi_uc *stbi__pic_load_core(stbi__context *s, int width, int height, int *comp, stbi_uc *result)
{
   int act_comp = 0, num_packets = 0, y, chained;
   stbi__pic_packet packets[10];

   // this will (should...) cater for even some bizarre stuff like having data
   // for the same channel in multiple packets.
   do
   {
      stbi__pic_packet *packet;

      if (num_packets == sizeof(packets) / sizeof(packets[0]))
         return stbi__errpuc("bad format", "too many packets");

      packet = &packets[num_packets++];

      chained = stbi__get8(s);
      packet->size = stbi__get8(s);
      packet->type = stbi__get8(s);
      packet->channel = stbi__get8(s);

      act_comp |= packet->channel;

      if (stbi__at_eof(s))
         return stbi__errpuc("bad file", "file too short (reading packets)");
      if (packet->size != 8)
         return stbi__errpuc("bad format", "packet isn't 8bpp");
   } while (chained);

   *comp = (act_comp & 0x10 ? 4 : 3); // has alpha channel?

   for (y = 0; y < height; ++y)
   {
      int packet_idx;

      for (packet_idx = 0; packet_idx < num_packets; ++packet_idx)
      {
         stbi__pic_packet *packet = &packets[packet_idx];
         stbi_uc *dest = result + y * width * 4;

         switch (packet->type)
         {
         default:
            return stbi__errpuc("bad format", "packet has bad compression type");

         case 0:
         { //uncompressed
            int x;

            for (x = 0; x < width; ++x, dest += 4)
               if (!stbi__readval(s, packet->channel, dest))
                  return 0;
            break;
         }

         case 1: //Pure RLE
         {
            int left = width, i;

            while (left > 0)
            {
               stbi_uc count, value[4];

               count = stbi__get8(s);
               if (stbi__at_eof(s))
                  return stbi__errpuc("bad file", "file too short (pure read count)");

               if (count > left)
                  count = (stbi_uc)left;

               if (!stbi__readval(s, packet->channel, value))
                  return 0;

               for (i = 0; i < count; ++i, dest += 4)
                  stbi__copyval(packet->channel, dest, value);
               left -= count;
            }
         }
         break;

         case 2:
         { //Mixed RLE
            int left = width;
            while (left > 0)
            {
               int count = stbi__get8(s), i;
               if (stbi__at_eof(s))
                  return stbi__errpuc("bad file", "file too short (mixed read count)");

               if (count >= 128)
               { // Repeated
                  stbi_uc value[4];

                  if (count == 128)
                     count = stbi__get16be(s);
                  else
                     count -= 127;
                  if (count > left)
                     return stbi__errpuc("bad file", "scanline overrun");

                  if (!stbi__readval(s, packet->channel, value))
                     return 0;

                  for (i = 0; i < count; ++i, dest += 4)
                     stbi__copyval(packet->channel, dest, value);
               }
               else
               { // Raw
                  ++count;
                  if (count > left)
                     return stbi__errpuc("bad file", "scanline overrun");

                  for (i = 0; i < count; ++i, dest += 4)
                     if (!stbi__readval(s, packet->channel, dest))
                        return 0;
               }
               left -= count;
            }
            break;
         }
         }
      }
   }

   return result;
}

static void *stbi__pic_load(stbi__context *s, int *px, int *py, int *comp, int req_comp, stbi__result_info *ri)
{
   stbi_uc *result;
   int i, x, y, internal_comp;
   STBI_NOTUSED(ri);

   if (!comp)
      comp = &internal_comp;

   for (i = 0; i < 92; ++i)
      stbi__get8(s);

   x = stbi__get16be(s);
   y = stbi__get16be(s);
   if (stbi__at_eof(s))
      return stbi__errpuc("bad file", "file too short (pic header)");
   if (!stbi__mad3sizes_valid(x, y, 4, 0))
      return stbi__errpuc("too large", "PIC image too large to decode");

   stbi__get32be(s); //skip `ratio'
   stbi__get16be(s); //skip `fields'
   stbi__get16be(s); //skip `pad'

   // intermediate buffer is RGBA
   result = (stbi_uc *)stbi__malloc_mad3(x, y, 4, 0);
   memset(result, 0xff, x * y * 4);

   if (!stbi__pic_load_core(s, x, y, comp, result))
   {
      STBI_FREE(result);
      result = 0;
   }
   *px = x;
   *py = y;
   if (req_comp == 0)
      req_comp = *comp;
   result = stbi__convert_format(result, 4, req_comp, x, y);

   return result;
}

static int stbi__pic_test(stbi__context *s)
{
   int r = stbi__pic_test_core(s);
   stbi__rewind(s);
   return r;
}
#endif

// *************************************************************************************************
// GIF loader -- public domain by Jean-Marc Lienher -- simplified/shrunk by stb

#ifndef STBI_NO_GIF
typedef struct
{
   stbi__int16 prefix;
   stbi_uc first;
   stbi_uc suffix;
} stbi__gif_lzw;

typedef struct
{
   int w, h;
   stbi_uc *out;        // output buffer (always 4 components)
   stbi_uc *background; // The current "background" as far as a gif is concerned
   stbi_uc *history;
   int flags, bgindex, ratio, transparent, eflags;
   stbi_uc pal[256][4];
   stbi_uc lpal[256][4];
   stbi__gif_lzw codes[8192];
   stbi_uc *color_table;
   int parse, step;
   int lflags;
   int start_x, start_y;
   int max_x, max_y;
   int cur_x, cur_y;
   int line_size;
   int delay;
} stbi__gif;

static int stbi__gif_test_raw(stbi__context *s)
{
   int sz;
   if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8')
      return 0;
   sz = stbi__get8(s);
   if (sz != '9' && sz != '7')
      return 0;
   if (stbi__get8(s) != 'a')
      return 0;
   return 1;
}

static int stbi__gif_test(stbi__context *s)
{
   int r = stbi__gif_test_raw(s);
   stbi__rewind(s);
   return r;
}

static void stbi__gif_parse_colortable(stbi__context *s, stbi_uc pal[256][4], int num_entries, int transp)
{
   int i;
   for (i = 0; i < num_entries; ++i)
   {
      pal[i][2] = stbi__get8(s);
      pal[i][1] = stbi__get8(s);
      pal[i][0] = stbi__get8(s);
      pal[i][3] = transp == i ? 0 : 255;
   }
}

static int stbi__gif_header(stbi__context *s, stbi__gif *g, int *comp, int is_info)
{
   stbi_uc version;
   if (stbi__get8(s) != 'G' || stbi__get8(s) != 'I' || stbi__get8(s) != 'F' || stbi__get8(s) != '8')
      return stbi__err("not GIF", "Corrupt GIF");

   version = stbi__get8(s);
   if (version != '7' && version != '9')
      return stbi__err("not GIF", "Corrupt GIF");
   if (stbi__get8(s) != 'a')
      return stbi__err("not GIF", "Corrupt GIF");

   stbi__g_failure_reason = "";
   g->w = stbi__get16le(s);
   g->h = stbi__get16le(s);
   g->flags = stbi__get8(s);
   g->bgindex = stbi__get8(s);
   g->ratio = stbi__get8(s);
   g->transparent = -1;

   if (comp != 0)
      *comp = 4; // can't actually tell whether it's 3 or 4 until we parse the comments

   if (is_info)
      return 1;

   if (g->flags & 0x80)
      stbi__gif_parse_colortable(s, g->pal, 2 << (g->flags & 7), -1);

   return 1;
}

static int stbi__gif_info_raw(stbi__context *s, int *x, int *y, int *comp)
{
   stbi__gif *g = (stbi__gif *)stbi__malloc(sizeof(stbi__gif));
   if (!stbi__gif_header(s, g, comp, 1))
   {
      STBI_FREE(g);
      stbi__rewind(s);
      return 0;
   }
   if (x)
      *x = g->w;
   if (y)
      *y = g->h;
   STBI_FREE(g);
   return 1;
}

static void stbi__out_gif_code(stbi__gif *g, stbi__uint16 code)
{
   stbi_uc *p, *c;
   int idx;

   // recurse to decode the prefixes, since the linked-list is backwards,
   // and working backwards through an interleaved image would be nasty
   if (g->codes[code].prefix >= 0)
      stbi__out_gif_code(g, g->codes[code].prefix);

   if (g->cur_y >= g->max_y)
      return;

   idx = g->cur_x + g->cur_y;
   p = &g->out[idx];
   g->history[idx / 4] = 1;

   c = &g->color_table[g->codes[code].suffix * 4];
   if (c[3] > 128)
   { // don't render transparent pixels;
      p[0] = c[2];
      p[1] = c[1];
      p[2] = c[0];
      p[3] = c[3];
   }
   g->cur_x += 4;

   if (g->cur_x >= g->max_x)
   {
      g->cur_x = g->start_x;
      g->cur_y += g->step;

      while (g->cur_y >= g->max_y && g->parse > 0)
      {
         g->step = (1 << g->parse) * g->line_size;
         g->cur_y = g->start_y + (g->step >> 1);
         --g->parse;
      }
   }
}

static stbi_uc *stbi__process_gif_raster(stbi__context *s, stbi__gif *g)
{
   stbi_uc lzw_cs;
   stbi__int32 len, init_code;
   stbi__uint32 first;
   stbi__int32 codesize, codemask, avail, oldcode, bits, valid_bits, clear;
   stbi__gif_lzw *p;

   lzw_cs = stbi__get8(s);
   if (lzw_cs > 12)
      return NULL;
   clear = 1 << lzw_cs;
   first = 1;
   codesize = lzw_cs + 1;
   codemask = (1 << codesize) - 1;
   bits = 0;
   valid_bits = 0;
   for (init_code = 0; init_code < clear; init_code++)
   {
      g->codes[init_code].prefix = -1;
      g->codes[init_code].first = (stbi_uc)init_code;
      g->codes[init_code].suffix = (stbi_uc)init_code;
   }

   // support no starting clear code
   avail = clear + 2;
   oldcode = -1;

   len = 0;
   for (;;)
   {
      if (valid_bits < codesize)
      {
         if (len == 0)
         {
            len = stbi__get8(s); // start new block
            if (len == 0)
               return g->out;
         }
         --len;
         bits |= (stbi__int32)stbi__get8(s) << valid_bits;
         valid_bits += 8;
      }
      else
      {
         stbi__int32 code = bits & codemask;
         bits >>= codesize;
         valid_bits -= codesize;
         // @OPTIMIZE: is there some way we can accelerate the non-clear path?
         if (code == clear)
         { // clear code
            codesize = lzw_cs + 1;
            codemask = (1 << codesize) - 1;
            avail = clear + 2;
            oldcode = -1;
            first = 0;
         }
         else if (code == clear + 1)
         { // end of stream code
            stbi__skip(s, len);
            while ((len = stbi__get8(s)) > 0)
               stbi__skip(s, len);
            return g->out;
         }
         else if (code <= avail)
         {
            if (first)
            {
               return stbi__errpuc("no clear code", "Corrupt GIF");
            }

            if (oldcode >= 0)
            {
               p = &g->codes[avail++];
               if (avail > 8192)
               {
                  return stbi__errpuc("too many codes", "Corrupt GIF");
               }

               p->prefix = (stbi__int16)oldcode;
               p->first = g->codes[oldcode].first;
               p->suffix = (code == avail) ? p->first : g->codes[code].first;
            }
            else if (code == avail)
               return stbi__errpuc("illegal code in raster", "Corrupt GIF");

            stbi__out_gif_code(g, (stbi__uint16)code);

            if ((avail & codemask) == 0 && avail <= 0x0FFF)
            {
               codesize++;
               codemask = (1 << codesize) - 1;
            }

            oldcode = code;
         }
         else
         {
            return stbi__errpuc("illegal code in raster", "Corrupt GIF");
         }
      }
   }
}

// this function is designed to support animated gifs, although stb_image doesn't support it
// two back is the image from two frames ago, used for a very specific disposal format
static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, int req_comp, stbi_uc *two_back)
{
   int dispose;
   int first_frame;
   int pi;
   int pcount;
   STBI_NOTUSED(req_comp);

   // on first frame, any non-written pixels get the background colour (non-transparent)
   first_frame = 0;
   if (g->out == 0)
   {
      if (!stbi__gif_header(s, g, comp, 0))
         return 0; // stbi__g_failure_reason set by stbi__gif_header
      if (!stbi__mad3sizes_valid(4, g->w, g->h, 0))
         return stbi__errpuc("too large", "GIF image is too large");
      pcount = g->w * g->h;
      g->out = (stbi_uc *)stbi__malloc(4 * pcount);
      g->background = (stbi_uc *)stbi__malloc(4 * pcount);
      g->history = (stbi_uc *)stbi__malloc(pcount);
      if (!g->out || !g->background || !g->history)
         return stbi__errpuc("outofmem", "Out of memory");

      // image is treated as "transparent" at the start - ie, nothing overwrites the current background;
      // background colour is only used for pixels that are not rendered first frame, after that "background"
      // color refers to the color that was there the previous frame.
      memset(g->out, 0x00, 4 * pcount);
      memset(g->background, 0x00, 4 * pcount); // state of the background (starts transparent)
      memset(g->history, 0x00, pcount);        // pixels that were affected previous frame
      first_frame = 1;
   }
   else
   {
      // second frame - how do we dispoase of the previous one?
      dispose = (g->eflags & 0x1C) >> 2;
      pcount = g->w * g->h;

      if ((dispose == 3) && (two_back == 0))
      {
         dispose = 2; // if I don't have an image to revert back to, default to the old background
      }

      if (dispose == 3)
      { // use previous graphic
         for (pi = 0; pi < pcount; ++pi)
         {
            if (g->history[pi])
            {
               memcpy(&g->out[pi * 4], &two_back[pi * 4], 4);
            }
         }
      }
      else if (dispose == 2)
      {
         // restore what was changed last frame to background before that frame;
         for (pi = 0; pi < pcount; ++pi)
         {
            if (g->history[pi])
            {
               memcpy(&g->out[pi * 4], &g->background[pi * 4], 4);
            }
         }
      }
      else
      {
         // This is a non-disposal case eithe way, so just
         // leave the pixels as is, and they will become the new background
         // 1: do not dispose
         // 0:  not specified.
      }

      // background is what out is after the undoing of the previou frame;
      memcpy(g->background, g->out, 4 * g->w * g->h);
   }

   // clear my history;
   memset(g->history, 0x00, g->w * g->h); // pixels that were affected previous frame

   for (;;)
   {
      int tag = stbi__get8(s);
      switch (tag)
      {
      case 0x2C: /* Image Descriptor */
      {
         stbi__int32 x, y, w, h;
         stbi_uc *o;

         x = stbi__get16le(s);
         y = stbi__get16le(s);
         w = stbi__get16le(s);
         h = stbi__get16le(s);
         if (((x + w) > (g->w)) || ((y + h) > (g->h)))
            return stbi__errpuc("bad Image Descriptor", "Corrupt GIF");

         g->line_size = g->w * 4;
         g->start_x = x * 4;
         g->start_y = y * g->line_size;
         g->max_x = g->start_x + w * 4;
         g->max_y = g->start_y + h * g->line_size;
         g->cur_x = g->start_x;
         g->cur_y = g->start_y;

         // if the width of the specified rectangle is 0, that means
         // we may not see *any* pixels or the image is malformed;
         // to make sure this is caught, move the current y down to
         // max_y (which is what out_gif_code checks).
         if (w == 0)
            g->cur_y = g->max_y;

         g->lflags = stbi__get8(s);

         if (g->lflags & 0x40)
         {
            g->step = 8 * g->line_size; // first interlaced spacing
            g->parse = 3;
         }
         else
         {
            g->step = g->line_size;
            g->parse = 0;
         }

         if (g->lflags & 0x80)
         {
            stbi__gif_parse_colortable(s, g->lpal, 2 << (g->lflags & 7), g->eflags & 0x01 ? g->transparent : -1);
            g->color_table = (stbi_uc *)g->lpal;
         }
         else if (g->flags & 0x80)
         {
            g->color_table = (stbi_uc *)g->pal;
         }
         else
            return stbi__errpuc("missing color table", "Corrupt GIF");

         o = stbi__process_gif_raster(s, g);
         if (!o)
            return NULL;

         // if this was the first frame,
         pcount = g->w * g->h;
         if (first_frame && (g->bgindex > 0))
         {
            // if first frame, any pixel not drawn to gets the background color
            for (pi = 0; pi < pcount; ++pi)
            {
               if (g->history[pi] == 0)
               {
                  g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It will be reset next frame if need be;
                  memcpy(&g->out[pi * 4], &g->pal[g->bgindex], 4);
               }
            }
         }

         return o;
      }

      case 0x21: // Comment Extension.
      {
         int len;
         int ext = stbi__get8(s);
         if (ext == 0xF9)
         { // Graphic Control Extension.
            len = stbi__get8(s);
            if (len == 4)
            {
               g->eflags = stbi__get8(s);
               g->delay = 10 * stbi__get16le(s); // delay - 1/100th of a second, saving as 1/1000ths.

               // unset old transparent
               if (g->transparent >= 0)
               {
                  g->pal[g->transparent][3] = 255;
               }
               if (g->eflags & 0x01)
               {
                  g->transparent = stbi__get8(s);
                  if (g->transparent >= 0)
                  {
                     g->pal[g->transparent][3] = 0;
                  }
               }
               else
               {
                  // don't need transparent
                  stbi__skip(s, 1);
                  g->transparent = -1;
               }
            }
            else
            {
               stbi__skip(s, len);
               break;
            }
         }
         while ((len = stbi__get8(s)) != 0)
         {
            stbi__skip(s, len);
         }
         break;
      }

      case 0x3B:              // gif stream termination code
         return (stbi_uc *)s; // using '1' causes warning on some compilers

      default:
         return stbi__errpuc("unknown code", "Corrupt GIF");
      }
   }
}

static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
{
   if (stbi__gif_test(s))
   {
      int layers = 0;
      stbi_uc *u = 0;
      stbi_uc *out = 0;
      stbi_uc *two_back = 0;
      stbi__gif g;
      int stride;
      memset(&g, 0, sizeof(g));
      if (delays)
      {
         *delays = 0;
      }

      do
      {
         u = stbi__gif_load_next(s, &g, comp, req_comp, two_back);
         if (u == (stbi_uc *)s)
            u = 0; // end of animated gif marker

         if (u)
         {
            *x = g.w;
            *y = g.h;
            ++layers;
            stride = g.w * g.h * 4;

            if (out)
            {
               void *tmp = (stbi_uc *)STBI_REALLOC(out, layers * stride);
               if (NULL == tmp)
               {
                  STBI_FREE(g.out);
                  STBI_FREE(g.history);
                  STBI_FREE(g.background);
                  return stbi__errpuc("outofmem", "Out of memory");
               }
               else
                  out = (stbi_uc *)tmp;
               if (delays)
               {
                  *delays = (int *)STBI_REALLOC(*delays, sizeof(int) * layers);
               }
            }
            else
            {
               out = (stbi_uc *)stbi__malloc(layers * stride);
               if (delays)
               {
                  *delays = (int *)stbi__malloc(layers * sizeof(int));
               }
            }
            memcpy(out + ((layers - 1) * stride), u, stride);
            if (layers >= 2)
            {
               two_back = out - 2 * stride;
            }

            if (delays)
            {
               (*delays)[layers - 1U] = g.delay;
            }
         }
      } while (u != 0);

      // free temp buffer;
      STBI_FREE(g.out);
      STBI_FREE(g.history);
      STBI_FREE(g.background);

      // do the final conversion after loading everything;
      if (req_comp && req_comp != 4)
         out = stbi__convert_format(out, 4, req_comp, layers * g.w, g.h);

      *z = layers;
      return out;
   }
   else
   {
      return stbi__errpuc("not GIF", "Image was not as a gif type.");
   }
}

static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
{
   stbi_uc *u = 0;
   stbi__gif g;
   memset(&g, 0, sizeof(g));
   STBI_NOTUSED(ri);

   u = stbi__gif_load_next(s, &g, comp, req_comp, 0);
   if (u == (stbi_uc *)s)
      u = 0; // end of animated gif marker
   if (u)
   {
      *x = g.w;
      *y = g.h;

      // moved conversion to after successful load so that the same
      // can be done for multiple frames.
      if (req_comp && req_comp != 4)
         u = stbi__convert_format(u, 4, req_comp, g.w, g.h);
   }
   else if (g.out)
   {
      // if there was an error and we allocated an image buffer, free it!
      STBI_FREE(g.out);
   }

   // free buffers needed for multiple frame loading;
   STBI_FREE(g.history);
   STBI_FREE(g.background);

   return u;
}

static int stbi__gif_info(stbi__context *s, int *x, int *y, int *comp)
{
   return stbi__gif_info_raw(s, x, y, comp);
}
#endif

// *************************************************************************************************
// Radiance RGBE HDR loader
// originally by Nicolas Schulz
#ifndef STBI_NO_HDR
static int stbi__hdr_test_core(stbi__context *s, const char *signature)
{
   int i;
   for (i = 0; signature[i]; ++i)
      if (stbi__get8(s) != signature[i])
         return 0;
   stbi__rewind(s);
   return 1;
}

static int stbi__hdr_test(stbi__context *s)
{
   int r = stbi__hdr_test_core(s, "#?RADIANCE\n");
   stbi__rewind(s);
   if (!r)
   {
      r = stbi__hdr_test_core(s, "#?RGBE\n");
      stbi__rewind(s);
   }
   return r;
}

#define STBI__HDR_BUFLEN 1024
static char *stbi__hdr_gettoken(stbi__context *z, char *buffer)
{
   int len = 0;
   char c = '\0';

   c = (char)stbi__get8(z);

   while (!stbi__at_eof(z) && c != '\n')
   {
      buffer[len++] = c;
      if (len == STBI__HDR_BUFLEN - 1)
      {
         // flush to end of line
         while (!stbi__at_eof(z) && stbi__get8(z) != '\n')
            ;
         break;
      }
      c = (char)stbi__get8(z);
   }

   buffer[len] = 0;
   return buffer;
}

static void stbi__hdr_convert(float *output, stbi_uc *input, int req_comp)
{
   if (input[3] != 0)
   {
      float f1;
      // Exponent
      f1 = (float)ldexp(1.0f, input[3] - (int)(128 + 8));
      if (req_comp <= 2)
         output[0] = (input[0] + input[1] + input[2]) * f1 / 3;
      else
      {
         output[0] = input[0] * f1;
         output[1] = input[1] * f1;
         output[2] = input[2] * f1;
      }
      if (req_comp == 2)
         output[1] = 1;
      if (req_comp == 4)
         output[3] = 1;
   }
   else
   {
      switch (req_comp)
      {
      case 4:
         output[3] = 1; /* fallthrough */
      case 3:
         output[0] = output[1] = output[2] = 0;
         break;
      case 2:
         output[1] = 1; /* fallthrough */
      case 1:
         output[0] = 0;
         break;
      }
   }
}

static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
{
   char buffer[STBI__HDR_BUFLEN];
   char *token;
   int valid = 0;
   int width, height;
   stbi_uc *scanline;
   float *hdr_data;
   int len;
   unsigned char count, value;
   int i, j, k, c1, c2, z;
   const char *headerToken;
   STBI_NOTUSED(ri);

   // Check identifier
   headerToken = stbi__hdr_gettoken(s, buffer);
   if (strcmp(headerToken, "#?RADIANCE") != 0 && strcmp(headerToken, "#?RGBE") != 0)
      return stbi__errpf("not HDR", "Corrupt HDR image");

   // Parse header
   for (;;)
   {
      token = stbi__hdr_gettoken(s, buffer);
      if (token[0] == 0)
         break;
      if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0)
         valid = 1;
   }

   if (!valid)
      return stbi__errpf("unsupported format", "Unsupported HDR format");

   // Parse width and height
   // can't use sscanf() if we're not using stdio!
   token = stbi__hdr_gettoken(s, buffer);
   if (strncmp(token, "-Y ", 3))
      return stbi__errpf("unsupported data layout", "Unsupported HDR format");
   token += 3;
   height = (int)strtol(token, &token, 10);
   while (*token == ' ')
      ++token;
   if (strncmp(token, "+X ", 3))
      return stbi__errpf("unsupported data layout", "Unsupported HDR format");
   token += 3;
   width = (int)strtol(token, NULL, 10);

   *x = width;
   *y = height;

   if (comp)
      *comp = 3;
   if (req_comp == 0)
      req_comp = 3;

   if (!stbi__mad4sizes_valid(width, height, req_comp, sizeof(float), 0))
      return stbi__errpf("too large", "HDR image is too large");

   // Read data
   hdr_data = (float *)stbi__malloc_mad4(width, height, req_comp, sizeof(float), 0);
   if (!hdr_data)
      return stbi__errpf("outofmem", "Out of memory");

   // Load image data
   // image data is stored as some number of sca
   if (width < 8 || width >= 32768)
   {
      // Read flat data
      for (j = 0; j < height; ++j)
      {
         for (i = 0; i < width; ++i)
         {
            stbi_uc rgbe[4];
         main_decode_loop:
            stbi__getn(s, rgbe, 4);
            stbi__hdr_convert(hdr_data + j * width * req_comp + i * req_comp, rgbe, req_comp);
         }
      }
   }
   else
   {
      // Read RLE-encoded data
      scanline = NULL;

      for (j = 0; j < height; ++j)
      {
         c1 = stbi__get8(s);
         c2 = stbi__get8(s);
         len = stbi__get8(s);
         if (c1 != 2 || c2 != 2 || (len & 0x80))
         {
            // not run-length encoded, so we have to actually use THIS data as a decoded
            // pixel (note this can't be a valid pixel--one of RGB must be >= 128)
            stbi_uc rgbe[4];
            rgbe[0] = (stbi_uc)c1;
            rgbe[1] = (stbi_uc)c2;
            rgbe[2] = (stbi_uc)len;
            rgbe[3] = (stbi_uc)stbi__get8(s);
            stbi__hdr_convert(hdr_data, rgbe, req_comp);
            i = 1;
            j = 0;
            STBI_FREE(scanline);
            goto main_decode_loop; // yes, this makes no sense
         }
         len <<= 8;
         len |= stbi__get8(s);
         if (len != width)
         {
            STBI_FREE(hdr_data);
            STBI_FREE(scanline);
            return stbi__errpf("invalid decoded scanline length", "corrupt HDR");
         }
         if (scanline == NULL)
         {
            scanline = (stbi_uc *)stbi__malloc_mad2(width, 4, 0);
            if (!scanline)
            {
               STBI_FREE(hdr_data);
               return stbi__errpf("outofmem", "Out of memory");
            }
         }

         for (k = 0; k < 4; ++k)
         {
            int nleft;
            i = 0;
            while ((nleft = width - i) > 0)
            {
               count = stbi__get8(s);
               if (count > 128)
               {
                  // Run
                  value = stbi__get8(s);
                  count -= 128;
                  if (count > nleft)
                  {
                     STBI_FREE(hdr_data);
                     STBI_FREE(scanline);
                     return stbi__errpf("corrupt", "bad RLE data in HDR");
                  }
                  for (z = 0; z < count; ++z)
                     scanline[i++ * 4 + k] = value;
               }
               else
               {
                  // Dump
                  if (count > nleft)
                  {
                     STBI_FREE(hdr_data);
                     STBI_FREE(scanline);
                     return stbi__errpf("corrupt", "bad RLE data in HDR");
                  }
                  for (z = 0; z < count; ++z)
                     scanline[i++ * 4 + k] = stbi__get8(s);
               }
            }
         }
         for (i = 0; i < width; ++i)
            stbi__hdr_convert(hdr_data + (j * width + i) * req_comp, scanline + i * 4, req_comp);
      }
      if (scanline)
         STBI_FREE(scanline);
   }

   return hdr_data;
}

static int stbi__hdr_info(stbi__context *s, int *x, int *y, int *comp)
{
   char buffer[STBI__HDR_BUFLEN];
   char *token;
   int valid = 0;
   int dummy;

   if (!x)
      x = &dummy;
   if (!y)
      y = &dummy;
   if (!comp)
      comp = &dummy;

   if (stbi__hdr_test(s) == 0)
   {
      stbi__rewind(s);
      return 0;
   }

   for (;;)
   {
      token = stbi__hdr_gettoken(s, buffer);
      if (token[0] == 0)
         break;
      if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0)
         valid = 1;
   }

   if (!valid)
   {
      stbi__rewind(s);
      return 0;
   }
   token = stbi__hdr_gettoken(s, buffer);
   if (strncmp(token, "-Y ", 3))
   {
      stbi__rewind(s);
      return 0;
   }
   token += 3;
   *y = (int)strtol(token, &token, 10);
   while (*token == ' ')
      ++token;
   if (strncmp(token, "+X ", 3))
   {
      stbi__rewind(s);
      return 0;
   }
   token += 3;
   *x = (int)strtol(token, NULL, 10);
   *comp = 3;
   return 1;
}
#endif // STBI_NO_HDR

#ifndef STBI_NO_BMP
static int stbi__bmp_info(stbi__context *s, int *x, int *y, int *comp)
{
   void *p;
   stbi__bmp_data info;

   info.all_a = 255;
   p = stbi__bmp_parse_header(s, &info);
   stbi__rewind(s);
   if (p == NULL)
      return 0;
   if (x)
      *x = s->img_x;
   if (y)
      *y = s->img_y;
   if (comp)
   {
      if (info.bpp == 24 && info.ma == 0xff000000)
         *comp = 3;
      else
         *comp = info.ma ? 4 : 3;
   }
   return 1;
}
#endif

#ifndef STBI_NO_PSD
static int stbi__psd_info(stbi__context *s, int *x, int *y, int *comp)
{
   int channelCount, dummy, depth;
   if (!x)
      x = &dummy;
   if (!y)
      y = &dummy;
   if (!comp)
      comp = &dummy;
   if (stbi__get32be(s) != 0x38425053)
   {
      stbi__rewind(s);
      return 0;
   }
   if (stbi__get16be(s) != 1)
   {
      stbi__rewind(s);
      return 0;
   }
   stbi__skip(s, 6);
   channelCount = stbi__get16be(s);
   if (channelCount < 0 || channelCount > 16)
   {
      stbi__rewind(s);
      return 0;
   }
   *y = stbi__get32be(s);
   *x = stbi__get32be(s);
   depth = stbi__get16be(s);
   if (depth != 8 && depth != 16)
   {
      stbi__rewind(s);
      return 0;
   }
   if (stbi__get16be(s) != 3)
   {
      stbi__rewind(s);
      return 0;
   }
   *comp = 4;
   return 1;
}

static int stbi__psd_is16(stbi__context *s)
{
   int channelCount, depth;
   if (stbi__get32be(s) != 0x38425053)
   {
      stbi__rewind(s);
      return 0;
   }
   if (stbi__get16be(s) != 1)
   {
      stbi__rewind(s);
      return 0;
   }
   stbi__skip(s, 6);
   channelCount = stbi__get16be(s);
   if (channelCount < 0 || channelCount > 16)
   {
      stbi__rewind(s);
      return 0;
   }
   (void)stbi__get32be(s);
   (void)stbi__get32be(s);
   depth = stbi__get16be(s);
   if (depth != 16)
   {
      stbi__rewind(s);
      return 0;
   }
   return 1;
}
#endif

#ifndef STBI_NO_PIC
static int stbi__pic_info(stbi__context *s, int *x, int *y, int *comp)
{
   int act_comp = 0, num_packets = 0, chained, dummy;
   stbi__pic_packet packets[10];

   if (!x)
      x = &dummy;
   if (!y)
      y = &dummy;
   if (!comp)
      comp = &dummy;

   if (!stbi__pic_is4(s, "\x53\x80\xF6\x34"))
   {
      stbi__rewind(s);
      return 0;
   }

   stbi__skip(s, 88);

   *x = stbi__get16be(s);
   *y = stbi__get16be(s);
   if (stbi__at_eof(s))
   {
      stbi__rewind(s);
      return 0;
   }
   if ((*x) != 0 && (1 << 28) / (*x) < (*y))
   {
      stbi__rewind(s);
      return 0;
   }

   stbi__skip(s, 8);

   do
   {
      stbi__pic_packet *packet;

      if (num_packets == sizeof(packets) / sizeof(packets[0]))
         return 0;

      packet = &packets[num_packets++];
      chained = stbi__get8(s);
      packet->size = stbi__get8(s);
      packet->type = stbi__get8(s);
      packet->channel = stbi__get8(s);
      act_comp |= packet->channel;

      if (stbi__at_eof(s))
      {
         stbi__rewind(s);
         return 0;
      }
      if (packet->size != 8)
      {
         stbi__rewind(s);
         return 0;
      }
   } while (chained);

   *comp = (act_comp & 0x10 ? 4 : 3);

   return 1;
}
#endif

// *************************************************************************************************
// Portable Gray Map and Portable Pixel Map loader
// by Ken Miller
//
// PGM: http://netpbm.sourceforge.net/doc/pgm.html
// PPM: http://netpbm.sourceforge.net/doc/ppm.html
//
// Known limitations:
//    Does not support comments in the header section
//    Does not support ASCII image data (formats P2 and P3)
//    Does not support 16-bit-per-channel

#ifndef STBI_NO_PNM

static int stbi__pnm_test(stbi__context *s)
{
   char p, t;
   p = (char)stbi__get8(s);
   t = (char)stbi__get8(s);
   if (p != 'P' || (t != '5' && t != '6'))
   {
      stbi__rewind(s);
      return 0;
   }
   return 1;
}

static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
{
   stbi_uc *out;
   STBI_NOTUSED(ri);

   if (!stbi__pnm_info(s, (int *)&s->img_x, (int *)&s->img_y, (int *)&s->img_n))
      return 0;

   *x = s->img_x;
   *y = s->img_y;
   if (comp)
      *comp = s->img_n;

   if (!stbi__mad3sizes_valid(s->img_n, s->img_x, s->img_y, 0))
      return stbi__errpuc("too large", "PNM too large");

   out = (stbi_uc *)stbi__malloc_mad3(s->img_n, s->img_x, s->img_y, 0);
   if (!out)
      return stbi__errpuc("outofmem", "Out of memory");
   stbi__getn(s, out, s->img_n * s->img_x * s->img_y);

   if (req_comp && req_comp != s->img_n)
   {
      out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y);
      if (out == NULL)
         return out; // stbi__convert_format frees input on failure
   }
   return out;
}

static int stbi__pnm_isspace(char c)
{
   return c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f' || c == '\r';
}

static void stbi__pnm_skip_whitespace(stbi__context *s, char *c)
{
   for (;;)
   {
      while (!stbi__at_eof(s) && stbi__pnm_isspace(*c))
         *c = (char)stbi__get8(s);

      if (stbi__at_eof(s) || *c != '#')
         break;

      while (!stbi__at_eof(s) && *c != '\n' && *c != '\r')
         *c = (char)stbi__get8(s);
   }
}

static int stbi__pnm_isdigit(char c)
{
   return c >= '0' && c <= '9';
}

static int stbi__pnm_getinteger(stbi__context *s, char *c)
{
   int value = 0;

   while (!stbi__at_eof(s) && stbi__pnm_isdigit(*c))
   {
      value = value * 10 + (*c - '0');
      *c = (char)stbi__get8(s);
   }

   return value;
}

static int stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp)
{
   int maxv, dummy;
   char c, p, t;

   if (!x)
      x = &dummy;
   if (!y)
      y = &dummy;
   if (!comp)
      comp = &dummy;

   stbi__rewind(s);

   // Get identifier
   p = (char)stbi__get8(s);
   t = (char)stbi__get8(s);
   if (p != 'P' || (t != '5' && t != '6'))
   {
      stbi__rewind(s);
      return 0;
   }

   *comp = (t == '6') ? 3 : 1; // '5' is 1-component .pgm; '6' is 3-component .ppm

   c = (char)stbi__get8(s);
   stbi__pnm_skip_whitespace(s, &c);

   *x = stbi__pnm_getinteger(s, &c); // read width
   stbi__pnm_skip_whitespace(s, &c);

   *y = stbi__pnm_getinteger(s, &c); // read height
   stbi__pnm_skip_whitespace(s, &c);

   maxv = stbi__pnm_getinteger(s, &c); // read max value

   if (maxv > 255)
      return stbi__err("max value > 255", "PPM image not 8-bit");
   else
      return 1;
}
#endif

static int stbi__info_main(stbi__context *s, int *x, int *y, int *comp)
{
#ifndef STBI_NO_JPEG
   if (stbi__jpeg_info(s, x, y, comp))
      return 1;
#endif

#ifndef STBI_NO_PNG
   if (stbi__png_info(s, x, y, comp))
      return 1;
#endif

#ifndef STBI_NO_GIF
   if (stbi__gif_info(s, x, y, comp))
      return 1;
#endif

#ifndef STBI_NO_BMP
   if (stbi__bmp_info(s, x, y, comp))
      return 1;
#endif

#ifndef STBI_NO_PSD
   if (stbi__psd_info(s, x, y, comp))
      return 1;
#endif

#ifndef STBI_NO_PIC
   if (stbi__pic_info(s, x, y, comp))
      return 1;
#endif

#ifndef STBI_NO_PNM
   if (stbi__pnm_info(s, x, y, comp))
      return 1;
#endif

#ifndef STBI_NO_HDR
   if (stbi__hdr_info(s, x, y, comp))
      return 1;
#endif

// test tga last because it's a crappy test!
#ifndef STBI_NO_TGA
   if (stbi__tga_info(s, x, y, comp))
      return 1;
#endif
   return stbi__err("unknown image type", "Image not of any known type, or corrupt");
}

static int stbi__is_16_main(stbi__context *s)
{
#ifndef STBI_NO_PNG
   if (stbi__png_is16(s))
      return 1;
#endif

#ifndef STBI_NO_PSD
   if (stbi__psd_is16(s))
      return 1;
#endif

   return 0;
}

#ifndef STBI_NO_STDIO
STBIDEF int stbi_info(char const *filename, int *x, int *y, int *comp)
{
   FILE *f = stbi__fopen(filename, "rb");
   int result;
   if (!f)
      return stbi__err("can't fopen", "Unable to open file");
   result = stbi_info_from_file(f, x, y, comp);
   fclose(f);
   return result;
}

STBIDEF int stbi_info_from_file(FILE *f, int *x, int *y, int *comp)
{
   int r;
   stbi__context s;
   long pos = ftell(f);
   stbi__start_file(&s, f);
   r = stbi__info_main(&s, x, y, comp);
   fseek(f, pos, SEEK_SET);
   return r;
}

STBIDEF int stbi_is_16_bit(char const *filename)
{
   FILE *f = stbi__fopen(filename, "rb");
   int result;
   if (!f)
      return stbi__err("can't fopen", "Unable to open file");
   result = stbi_is_16_bit_from_file(f);
   fclose(f);
   return result;
}

STBIDEF int stbi_is_16_bit_from_file(FILE *f)
{
   int r;
   stbi__context s;
   long pos = ftell(f);
   stbi__start_file(&s, f);
   r = stbi__is_16_main(&s);
   fseek(f, pos, SEEK_SET);
   return r;
}
#endif // !STBI_NO_STDIO

STBIDEF int stbi_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp)
{
   stbi__context s;
   stbi__start_mem(&s, buffer, len);
   return stbi__info_main(&s, x, y, comp);
}

STBIDEF int stbi_info_from_callbacks(stbi_io_callbacks const *c, void *user, int *x, int *y, int *comp)
{
   stbi__context s;
   stbi__start_callbacks(&s, (stbi_io_callbacks *)c, user);
   return stbi__info_main(&s, x, y, comp);
}

STBIDEF int stbi_is_16_bit_from_memory(stbi_uc const *buffer, int len)
{
   stbi__context s;
   stbi__start_mem(&s, buffer, len);
   return stbi__is_16_main(&s);
}

STBIDEF int stbi_is_16_bit_from_callbacks(stbi_io_callbacks const *c, void *user)
{
   stbi__context s;
   stbi__start_callbacks(&s, (stbi_io_callbacks *)c, user);
   return stbi__is_16_main(&s);
}
